Got a scope that arrived with out battery It is a Baska 7 inch tactical red dot I need a battery how can I get a CR2032 3V Lintium battery

Depends on what you mean by a "Scope". If you mean a red dot or low mag tactical scope, some do have those.
If you are talking about a magnified optic above 3x or 4x, then it makes little sense because there is so much vibration that you wouldn't be able to see anything. Second, a machine gun is not a precision fire weapon. It uses mass-produced ammo that doesn't have very tight tolerances for powder load or bullet weight. It is an area fire weapon primarily for suppression.

just screw it back into the holder part of the laser

The large knob on top holds the battery. Should be a slot that a coin will fit in to remove the cover.

Off which way at 25 feet. If the gun is shooting low at this distance i would back off to 25 yards. It may shoot low because the scope is mounted a about 1 1/2 inch above the bore of the gun. In the 25 feet there is not enough bullet rise to compensate for that sight being that far above the bore. You may have to go with a red dot type or just add a laser if you are going to stick inside your 25 foot zone.

It is underneath the top piece of your RGB dial the part that says stealth tactical unscrews from the RGB indicator portion.

No, that doesn't sound stupid. It's always a good idea to get all the information before using firearms and their accessories, and I'm happy to help:

The large knob on top of the scope is the rheostat, which is used to turn on the red dot, and adjust the brightness. It can be adjusted from "1" (dimmest) to "11" (brightest). You'll have to be looking straight down the scope to see the red dot, since it is only visible when you're aiming. If you turn on the scope to the brightest setting, and you look through like you are aiming, and the red dot is still not there (or very dim) then you probably need to replace the battery. It uses a 3 Volt coin-style lithium battery, type 2032. Unscrew the battery compartment on top of the rheostat and put the new battery "+" side up. Then replace the battery cover, and you should be good to go. Turn off the scope when you're done to save the batteries.

Since you bought the rifle with the scope already installed, it's probably already sighted in, or pretty close to being sighted in. Adjusting the windage and elevation on the red dot scope works just like other rifle scopes. The knob on top moves the point of impact up/down, and the knob on the side moves left/right. For this model, each click of adjustment moves the point fo impact by 1/2" at 100 yds, 1/4" at 50 yds, or 1/8" at 25 yds.

Be safe, and have fun!

Try

Take the scope to the battery store with you. I would bet that it is a 2032.

The PDP3CMP uses the CR2032 batteries.I had one and gave it to my son who uses it on a huge pistol.I gace him several spare batteries with it.You always need a spare for those things.Good Luck