Problem with importing or setting up a character that consist of multiple separate meshes (Robot)

I have searched everywhere and I am out of time almost on my college project hand in. My problem is I made a Bionicle Character and used biped in 3ds max 2017 to animate him, When I import to unreal it import some of the parts separate. My question is how do I combine everything in UE4? or am I doing something wrong in 3ds max? Any help would be appreciated. Or links to tutorials or help bc I cant find any. The only I can find is where the character are one object.