First of all, if you just want to attach an object to your character, you can do that by adding the mesh as a component in your character BP and attaching it to a socket. (You may have to make the socket on the skeleton if your character doesn’t already have one).
Second, if you want to loop animations, I believe you can set montage sections to loop on each other (though usually that is only done if you are planning to have some condition under which the loop will stop; its not intended to be infinite), or in the animation blueprint, there is a checkbox to loop an animation.