How do you set animations to a different mesh set?

I want to duplicate animations that come with an FPP gun animation pack I bought and I can’t figure out how to change the Skeletal Mesh with a different skeleton.
Any help is appreciated.

The animations you bought most likely work with the standard UE4 skeleton, so you should be able to use them with any character that has that skeleton. If you are using a Mixamo character, take a look at this tutorial series by Epic where they show you how to retarget animations: