Can someone help me with Tweening, animations, and welding fake arms? [closed]

Section I. I'm currently trying to make my own FPS gun kit/engine and I'm running into a few issues. First off, I'm having trouble with tweening a few parts. The parts that I'm trying to tween are the (This is an M4) Bolt which is a union, and tween the mag. I'm having issues with this and I'm aboutta blow. How do I get these dang things to tween smoothly like in Phantom Forces?

Section II. The next thing I need help with is with making animations. :/ This.. My friends is the biggest mother trucker in my world. I really... Really... Really.. Need help with this. The Animations are basically for Tweening the arms, the reload animations, firing animations, blah blah blah.. So yea.. I really need help with this crap. If you find that messaging me on Roblox is easier, my Username is PercyDHunters.

Section III. The last thing.. For now, that I need help with is welding on fake arms. Just like the ones you can see in Phantom forces or impulse, you know what I'm talking about I'm positive so.. I'm having issues with welding the dang thing to the player's torso.

Section IV. A few things.. Since this is an FPS engine, the guns will be stuck into the camera just like any professional gun engine. :/

I will be ever so grateful for those who can help me!