Simple gun/gun system tutorial? (Something similar to the Sk-4 in futuretops)

I want to make a simple gun system that is similar to the one used in future tops. Preferably the SK-4 gun. I have never made a gun before, and I cannot find any good tutorials that do what I want them to. I looked for youtube tutorials, I tried to find tutorials on the dev-forum, but I couldn’t find anything. I don’t want anybody to make any systems for me or write an entire script, I just want to know if I can find a good tutorial forum or video anywhere.