Tutorials are videos that will explain you step by step how you can create a weapon -> there is no better way to learn how to create one (except of private tutoring ;))
e.g here is a tutorial that I posted a while ago: https://forums.unrealengine/showthread.php?55508-How-to-integrate-Military-Weapons-pack-into-FPS&highlight=weapon (you dont need the weapon pack -> just your own weapon)