Hello, I would suggest using functions to create guis. You can call upon a function and open a new gui inside of a gui. I also recommend using TuSKe for guis.

 

TuSKe is glitchy, a lot of the times it flat out acts like a chest where you can just take items. Use vanilla GUIs.

They won't really work on Minehut, as 1.14+ has messed them up a bit, and to fix it you need Skript-mirror, but chances are you're not on Minehut.

Here's how to use them:

Code (Text):

1. command /example:
2.     trigger:
3.         open chest inventory with 1 row named "&euwu" to player
4.         set slot 0 of player to diamond ore named "Example"
5. on inventory click:
6.     if event.getView().getTitle() == "&euwu": # it's this, or getTitle().getView(), i dont remember 1000%.
7.         # here is the way I like to do it:
8.         if index of event-slot == 0:
9.             message "Yay!"
10.         # a more traditional way
11.         if event-slot == diamond ore named "Example":
12.             message "Yahoo!"

 

good, then that script will work.