To equip the gun you can add an empty node to the hand bone of your character and use it as the new parent node of the gun when you pick it up.
You’ll probably have to adjust the local position and orientation of the gun after that but it is as simple as that.
You should take a look at my resident evil type game “Chaos Emergency” i`m looking for talented people
to work on it with me, can you texture yourself and model ? and animate ? please let me know.
This looks really good for your first game! As for your gun problem, I don’t know enough about that to say anything. I really like the way this game looks, almost like AAA quality. You could probably get a job as a professional game designer. Good luck with the project, mate.