Advice Needed Unity how to import weapons with hand in my game

Hello, i tryed on unity but no body give someting back to me.
Really anoying im new i have MFPS unity assets and UFPS but dont really not understand how to add new weapons becauss i really have amazing weapons models for unity .fbx with hands etc... maked own but im really idiot with c# and dont now how to import to character i now drag and drop to unity but problem to bring it to have reload, shoot and etc... problem :( yt not help much.