Aw man, where to begin?
Check out all the info at the top of the Build forum for starters.
The NDS economy reciever is an excellent choice. It was designed to be used with a Century FCG. If you use a G2 FCG as I did you'll want to use a double hook model and file a extra groove underneath for the second hook. It'll be a groove about half the length of the already cut one. Or, get their premium reciever and a package deal from one of the vendors here to get yourself a G2 FCG, USA made gas piston and muzzle device so the rifle will be 922r compliant. DO look into 922 compliance. Basically you'll need a half dozen USA made parts in the rifle when you're done.
There are many excellent vendors here. I have dealt with most. I do know that Copes still has excellent all matching Romy G's in stock because I got two recently from them. They also sell all the compliance parts and have very reasonable shipping. CFS, DPH and others sell the kits too. I'm sure there are others.
You'll need a long and short rivet setting tool. You'll need a way to press out and reinstall the barrel pins and the barrel itself.
There's more, of course. But it's fascinating to learn.
There is a tutorial about building called "Soup to Nuts". They are huge pdf files, but if you have a high speed connection, I could e-mail them to you.
Welcome to the best AK forum! I hope you find what you need here as I have. Enjoy!