If 1 large scrap metal gives 3 or 2 scrap metal, where do we find/get large scrap metal or scrap metal in general? 

Scavenging entities.

someone moved the crafting table and since I knew where it was before would it not be meta if I could know?????

Also can you craft guns or can you just get them? Also do weapon making manuals come from scavenging entities such as trash piles?

Guns cannot be crafted however broken guns can be repaired. Weapon repair manuals can be found in scavenging piles, yes. Or obtained via roleplay.

"Obtained during role play" dont kid yourself fooz, look at this player base mang