How do I use dropdowns to change data in a table?

This is a pretty strange question and I don't know if I'm describing it right in my title, but basically in one spreadsheet I want to have one or two sheets with some data sets and then a third with a drop down menu that will display data from those other sheets. I know this is possible because I've seen it done with the Helldivers 2 Divers Dex, found here if you need an example of it: https://www.reddit.com/r/Helldivers/comments/1cec9l4/diversdex_your_pokedex_but_for_helldivers_2/

I don't need to do any calculations so my project should be a lot easier to work on. I already have all the data saved in one sheet but it's not easy to read, I just need to know how I could set up a display similar to how the creator of that other spreadsheet did it, I've also reached out to them and they did try to answer the question but I think they didn't understand me correctly and haven't gotten back when I reached out again.

If this answer requires Google Sheets then go ahead and tell me, It would be easy to switch my project to that program, but I'd still appreciate an answer.

Quick edit: I plan on hiding the sheets I'm puling the data from so users can't see them, it's not important for the question but some people might not understand why I want to use another sheet in the same file.