Minecraft doesn't really have a GUI api developers can use. This project takes advantage of the existing minecraft inventories in order to create interactable menus.
Here is the example provided with the code
Uncompressed: https://i.imgur.com/mHD83ty.gif
There is an example located on https://github.com/PatoTheBest/GUIFramework/tree/master/src/main/java/me/patothebest/guiframework/example
Others because github has a 5mb gif limit: