I really need help!

[Zolga14]

Ive been trying to figure out how to put an item from the Castlevania Weapons pack onto a Raichu model (the scythe onto the end of the tail instead of the bolt). Ive been looking for tutorials for the past 3 hours and havent found anything. Could someone please tell me how to import a weapon/object onto a character or replace a part on a character with an object???