How do i make those fps guns that go in camera and stuff?

FOR THE LAST ******* TIME THIS IS NOT A REQUEST

i see alot of games doing those first person arms and gun and i fowund a forum teaching how to make it aim but it didn't teached how to make fire and stuff and the script was brokeen, soo can someone tell me where should i start on making an viewmodel fps gun with viewport and stuff, ik how to put in camera but idk how to animate it :/