How to change weapons with blueprint Nazi Zombies style?

I want to remake Nazi Zombies from call of duty as a practice project. I need to know how to make it so that I start with 1 gun and the first gun I pick up will go to the second gun slot and then when i pick up a new gun it takes the place of the currently equipped gun. If you could explain a little about it to that would be great as Im looking to learn and not copy blueprint pictures. Thanks in advance.

You got any inventory system?

No I don’t.