youve got to rivet it, finish coat it, install the FCG, and then backwards field strip it. you probably wont even have to headspace it, since it was headspaced before it was demilled and it should have the same spacing when you reinstall the barrel (unless you go drilling new pin slots in it).
its not all that difficult, but everyone around here recommends building a Romy first. but i wouldnt imagine that a Yugo underfolder would be all that difficult compared to a Romy, so idont see why you wouldnt be able to do it.
and a polish one, dont build it on that reciever. that one's got the front trunnion swells in it for the Yugo, and the Polskis use a regular AKM reciever. unless you mean just the folding stock on that rifle, in which case im inclined to think it would fit all right.
hope this helps, and i hope you get in on a build one way or another