how to make a part of a gun move with animation?

hi i am making a gun and would like to know how to make a good reload animation.What i mean is have the mag move while the humanoid mesh whatever you wanna call it is playing its animation how would i animate them both at the same time?and i dont know how to rig so if it requires rigging i need a video or a friend request so you can show me my username jaycar9.also i want the animation to play in game and here is the gun itself

link below https://web.roblox.com/library/1476559281/best-scar-l-ever