Welcome to the forum bro!!!
Ask away, any questions you have, we are always here to help.
Anyway, congrats on the score, sounds like a good deal, huh?
Your dad is right, and you are on your way. Centered under the engine is your drain plug, pull it, let it empty out and re-fill with gear oil, about 650ML. Any light weight will work, I use the 20x70w ATV I think??? Sure others will chime in on what they use, but alot of products will work.
As for the gas, good it is empty but I would pull the tank and lines, run a cleaner through them, make sure lines and petcock are free from debris, rust, etc if any. (not likely) Also Put in a new spark plug, for sure.
Is the oil injection still hooked up? (tank under rear left of seat, this will be where your 2 stroke oil for injection will go if not deleted.) If it is, you have to pre-mix your gas oil at 32:1 ratio.
Be sure to lube your chain with some good chain lube, love the Bel-Ray products. Most of this stuff can be purchased online, cheap, or available at your local shop if ya wanna grab it quick.
Pressurize the tires to recommended pressure depending on what kind of tires are on the bike.
With the carb, yes, it needs to be cleaned. Remove the carb from the bike by loosening the clamps where the intake meets and the reed cage mounts at the front of the engine. Pull the carb from the bike, you can leave the TORS head(big unit on top of carb) attached, carb will still come off the bike far enough to work on. Remove the Reed block and inspect the reeds for damage, etc. Remove the bottom carb pan and inspect the floats for proper clearance and movement. Remove the jets and poke through clean with wire, spray carb cleaner through, etc. Be sure to clean all internals of Carb, remove any debris, etc.
This should get you started, but assure everything is clean and covered here, this will get that bike fired back up, and then we can continue to get you up and running and going with your new blaster.
be sure to give us more info, get pics up if ya can, etc.
Good luck!!!! I:I