How do I install needle plate on model 8763

What exactly is the difficulty? Is it half flat backed or completely round? If you can give more info, I may be able to help. :-)

This can happen easily on older machines if you pull out the slide plate a little too far. If the bottom of the slide plate has a flat spring that should have keep it in, then the way to get it back is:
1 Remove the needle, presser foot and needle plate.
2 Turn the handwheel toward you until the feed dogs are down.
3 Slide the plate into place, over the feed dogs, until the flat spring catches the machine bed.
Trying to wiggle it back in the way it came out has never worked for me.

The machine should be able to pull the fabric through without any assistance from the user. Pulling or pushing fabric will frequently cause the needle to bend and then break when it hits the needle plate or the hook. Flying pieces of broken needle can be very dangerous for you as well as damaging to the machine because it can knock the needle/hook out of time. (Uh-oh! Service time!)

Try installing a brand new needle specifically for the thread and fabric you are stitching. (Dull, nicked, or bent needles are probably the #1 sewing machine problem--an inexpensive fix for a very frustrating issue! Needles should be changed frequently or sooner if they are damaged.)

All About Needles

Some sewing machines also have a special accessory called a straight-stitch needle plate. Instead of having a horizontal rectangular shaped hole to accommodate the left-to-right needle swing to make a zig-zag stitch, there is a tiny round hole just big enough for the needle and thread to perform a straight stitch. The round needle hole is small enough to prevent or limit the chance of the fabric being pulled down into the bobbin area.

Straight stitch plate:
http://www.ebay.com/itm/like/271963297717?ul_noapp=true&chn=ps&lpid=82

Zig-zag Needle Plate:
https://www.google.com/search?q=Bernina+zig-zag+needle+plate&tbm=isch&imgil=PXesGDP1gxgggM%253A%253B0OfvcjNTtGe5oM%253Bhttp%25253A%25252F%25252Fwww.thecolorfulworldofsewing.com%25252FNeedle-Plates-For-Bernina-1630.html&source=iu&pf=m&fir=PXesGDP1gxgggM%253A%252C0OfvcjNTtGe5oM%252C_&usg=__Y0Wg3M9kgo4z4_1s4emmMPxKMBg%3D&biw=1173&bih=520&ved=0ahUKEwih7O-z0orLAhVB-2MKHZV6AwMQyjcIKA&ei=SZ3KVuGjA8H2jwOV9Y0Y#imgrc=PXesGDP1gxgggM%3A

We really can't diagnose your problem without knowing the brand and model of your machine.

If it fit when you took it off, but you're having trouble putting it back on again, chances are you haven't put your bobbin case in correctly--that's why it won't fit. Review the placement of the case in your user's manual; if you can't locate it, you can download one free at the Singer Sewing Machine site.

insert the needle all the way up. if it is not a timing issue, try to lift the needle shaft

insert the needle all the way up or, lift the needle shaft and, if the problem persist's andjust the timing of the machine

Sometimes you have to manipulate the plate to get it to "settle" into its slots, but if it lined up before you took it off, it must line up now, IF your bobbin case is correctly inserted, which could be another possibility.

Please correct down position and remove the foot and switch off machine. Then set of the up position applique the needle. After machine On.

read the user manual and if you do not get anything from the trouble shooting section take it back for a warranty check as something may have moved from the material jam