how do i make a level map like super mario 3

I’m making a sidescrolling game and I found the perfect set of tutorials for the game but the only thing it is missing is how to make the map. I just want like a typical over world map like from super mario world, mario 3, super mario bros wii, that you can go from level to level, play/beat it and it unlocks the next one. Anyone know of any good tutorials?

You can check here, they are free tuts and are well explained :