12v rebuild for dummies

Hey guys I really want to learn how to rebuild a 12v... I hear to many bad stories about machine shops and anymore you can't trust a used engine because it's a gamble... i dont know where to start first on asking questions... I would break and fix myself but a engine rebuild can be pricey if I f*** up... any and all info will be greatly appericated.. all I want to do is stock rebuild for my 1st rebuild... I've tore them apart to block just nervous putting it all back together. Like tongue specs, what lube to use, the order of putting it back together etc. I would like for this thread to kind of turn into a step by step so it not only could help me but help others that read this thread. thanks guys in advance