How do you make a old weapon shop?

So recently I have been obsessed with this game called westbound. And I want to make a weapon shop like they have. Can anybody help me?

You should try to learn yourself first before asking questions. I'd recommend learning Lua in general, but also using some resources such as the Roblox References.

You might find this helpful: https://developer.roblox.com/en-us/api-reference/class/ScreenGui