The feed dogs will not pull the material through. they do not seem to me coming up high enough to clear the foot plate. I cannot find an adjustment to raise them.

1. It most likely is the foot pressure not set properly. With thick material it needs to be less and with thin material it is opposite. Just test a piece of like fabric that is rags.
2. Make sure that you clean out any thread under the plate as good as you can.
3. Check your tensions. The top should be around four. The bobbin tension has to be even with the top tension. (like tug of war) However, when you thread the top do it with the foot up to check for snags. Snags are a serious problem and cause the material from moving. Good Luck.

Be sure you have the stitch length set high enough that the fabric will actually move instead of sewing mostly in one spot.

One other thing to check is the presser foot applying enough pressure to the fabric so that the feed dogs can grab the fabric? On the top left side of the machine, there is probably either a dial or a push-type button. That would most likely be the pressure adjustment. The tighter that is set, the harder the pressure the presser foot will apply and the more the feed dogs will grab the fabric.

Check that the feed dogs are in the "up" position so they will pull the fabric through the machine. Are the feed dogs actually moving forward, raising above the needle plate, pulling toward the back of the machine, and then dropping below the needleplate before moving forward again? If not, then the problem could be with the feed dogs.

Your machine appears to be a mechanical model. If so, it could be the machine needs a good over-all cleaning and oiling--a couple drops of fresh, good quality sewing machine oil every place that metal rubs on metal (no plastic parts, belts...). Feed dogs are frequently affected when the sewing machine does not receive regular maintenance.

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***Your feed dog under the pressure foot seems to be pulling on one side a little harder which indicates wear. It is likely to solve the problem by replacing the feed dog.
***Before you do this try to lower the pressure on the pressure foot. If the material you are sewing is thick it will have an effect on the pull of the feed dogs. The material you are sewing that you sent appears to be jeans material. It looks like it is thick and somewhat slippery.

Tension generally does not affect the feed unless it is way too tight. Most reasons for fabric not advancing under the presser foot is that the feed dogs have been dropped for darning. If the feed dogs are operating properly, as the handwheel turns the feed dogs should rise above the plate, move toward the back of the machine pulling the fabric, drop down, come forward and rise again.

The other possibility is that the presser foot pressure has been released so the presser foot is not holding the fabric down on the feed dogs. Some machines have a spring-loaded knob on the top of the machine, a dial, or something to adjust the amount of pressure the foot applies. Consult your owner's manual.

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Check to be sure you have not inadvertently dropped the feed dogs on your machine. Dropped feed dogs are used for 'darning' or 'free motion quilting.' Below is info from Troubleshooting Manual:

Fabric does not feed through the machine
The feed dogs are lowered. Use the feed dog position switch to raise the feed dogs. 81
The stitches are too close together. Lengthen the stitch length. 42
The wrong presser foot was used. Attach the correct presser foot. 179
The needle is bent or blunt. Replace the needle with a new one. 34
The thread is tangled. Use scissors, etc., to cut the tangled thread and remove it from the race, etc.

If you change the number of your stitch length it will automatically adjust the feed dogs. If it is still a problem then you will need it adjusted. Insure that your pressure foot is placing enough pressure that causes the feed dogs to pull the material forward. To adjust the feed dogs there are different ways to be adjusted. I wouldn't suggest you try to adjust the height of the feed dogs.

The waling foot sewing machine attachments I am familiar with don't exactly walk. They have a presser foot that glide over the cloth like every other presser foot. In addition they have feed dogs that work in unison with the feed dogs built in the machine. When the needle penetrates the material, the lower dogs drop and come forward and the upper dogs raise and come forward. As the needle exits the cloth,the lower dogs rise and pull the cloth while the upper dogs drop and pull the cloth. The arm on the attachment that operates the upper dogs rides on the screw that holds the needle. There is nothing to adjust.

Check whether the feed dogs are coming above the stitch-plate at their maximum height. They should be about 1mm above the stitch plate when driving the material under the foot. I assume, by the way, that you haven't got the feed-dog drop button pushed-in at the handwheel end !!! If the feed-dogs are lower than 1mm, or not above the stitch-plate, the dog cam cam-foller will need adjustment. You have to remove the front cover to get at this and it should be done with a special gauge, so really its a service agent job, however, for what its worth;
With the front cover removed to gain access to the free-arm mechanism, look to the right of the hook race and on the end of the bottom drive shaft there are two black plastic cams . The right-hand one regulates the movement of the dogs front-to-back in association with the stitch-length stepper-motor, which drives the upper shaft in the free-arm. The left-hand cam regulates the up-down movement of the dogs and the cam follower (a piece of right-angled plated metal) has to be adjusted to determine the maximum height of the dogs aboe the stitch plate. The cam follower rubs against the top edge of the dog cam. There should be a small spring that pulls the cam follower down onto the cam at the front - if that's missing, the feed-dogs probably wont move quite correctly. To adjust the dog height, turn the hand-wheel until the feed-dogs are at their maximum height, unscrew the small screw in the left-hand side of the cam follower a couple of turns (dont, for goodness-sake, take it out !) - the feed-dogs should then pop-up above the stitch-plate. You now have a problem without the proper gauge ! You need to gently push the dogs back down against spring pressure until they are the correct height above the stitch-plate and tighten the screw on the cam follower. This should, at least, get over the problem - it wont be exactly right without the gauge and there is another adjustment that should be done to ensure the front and back of the dogs are at slightly different heights, but it should be good enough without this.

Good Luck !!!

Remove the needle plate and check for lint build up between the feed dog teeth. Lint will build up and prevent the feed dogs from coming up all the way. I them still don't come up high enough, then they will have to be adjusted.

Feed dogs.

Check the manual for how to engage/raise the feed dogs.

Or, it could be the machine needs cleaning.

Open the bobbin area and the throat plate (plate under the presser foot) and clean with a soft brush or cotton swab.