How do I transfer bought items into an inventory gui when bought from a shop gui?

Hey, I've been trying to make an inventory gui system, so when something is bought from the shop gui, an image button of the item shows up in the player's inventory. However, upon further research, I found that I really shouldn't be editing the playergui, which I was doing. I used remote events, and, if bought, put the item into the player's playergui. I heard you should use a modulescript, but I'm confused as how this can be done. Any help would be appreciated! In short, my question is: I used to just edit playergui, but how do I use modulescripts for an inventory gui? Thanks for any help!