Minimap like BloodStained/Metroidvania

Hi guys, first of all thank you in advance. I’m trying to make a 3D metroid-style game as a college project. I would like to know how I could make a mini-map in the style of the Bloodstained game. Since I have looked both in forums and on the internet and I can not find information.
In this game, the rooms gradually appear when you enter them.
One more thing, if possible, do not recommend plugins to buy, I just want to know how to do it to learn.

Many thanks.