Help with skills to GUI slots

I need some help with making adjustable slot skills. For example, I want to make it so If I select a skill, I can choose to pick the available options I made on the skill list so I can pick what skill goes in said slot. This is for a One Punch man mod BTW I started a day ago so not too far into it besides creator creation and GUI stuff and base attributes. I imagine I can achieve this by making a bunch of separate global variables for each slot, so they save when u leave. But I am wondering if there is an easier way of achieving this.

Here is a the video link: https://imgur.com/ZLjRhyu 

Edit: Solved. Make a global string variable and put a list of words in (separate them with commas) to make a list. Use another variable to get information on what skill u clicked(like vari skill_selected = "normal punch"). Put it in one of the slots(a procedure when u click one of the slots) and search through the list using the index block in the text tab. If not vari skill_selected is in the list vari = 0 then store skill_selected in one of the slots.

Or just make a bunch of global variables for each slot lol

End result: https://i.imgur.com/QGsip2l.mp4