Animation Import problems

so i have problems with importing aimoffset animations to my pistol. So let me explain. I downloaded a free weapon pack from UE4 marketplace called Something like prototype_weapon_pack. It had knife pistol and other weapons. They also included the weapons skeletons and the mesh of course. I decided to just use the pistol as my main character/mesh. The problem is when i try to import aimoffset animations to the specific mesh ti gives an error message something like this ‘‘Your mesh contains Root_Bone1 as root but animation doesnt contain a root track’’.
So do i need to do something like name the animation bones same as the pistol bones, but how i do that and the animation bones are for a human skeleton so do i need to make my own for a pistol.
I would appreciate any type of help.
Thanks!