Hi, I’m not that far in the animation course, but I think I can point you in the right direction. It depends on the type of prop you have and how it’s going to behave, for some props you can use the character’s bones, for others you may need new bones. For example, you could parent the helmet to the head bone if you are not going to move it by itself or have the character take it off. If you want to animate it you may have to make new bones for it. For the gun, you may be able to do it by parenting it to a bone in the hand but sooner or later your character may need to holster that weapon.
In some videogames they use one bone for the location of the prop, this bone is usually part of the character’s armature. If the prop can move or has moving parts (for example, when you reload a shotgun) the prop may have it’s own armature.
