How do I create a GUI that saves the positions of tools?

I want to create a GUI that saves the position tools are in. For example, if I switched an item into the second slot of my backpack, I would want it to be in the same slot when I respawn. My main goal is to save the slot position of items that are in the player's starter pack. I just don't know where to start.

Well, if you need help starting, I will give you some advice. This answer does not contain code, but it does tell you good starting points. I suggest making a table right when the player dies, and taking the information out when the player respawns. Maybe you could use a For Key, Value do loop to cycle through all the tools and manage the information by storing it in a table. These are just some starting point ideas. Search up tables and storing information and how to use For Key Value do loops on the internet for more information. I hope this helps you. If it doesn't or you want to talk more about it, then comment in the comment section below.