I'm new, help plz

I'm new to this forum but have been playing Warcraft 3 for awhile, but in the World Editor, how do i make a map where it allows me to play as the Naga instead of the normal 4 races?

You will have to place the beginning units on the map first, like the Naga town hall, 5 Mur'gul slaves, and a gold mine if needed.

Then, go to the player properties and set the player control slot to Human. Don't be fooled by the name, as long as the units are placed, the race that you select will not matter.

Also, in the trigger editor, there are actions that will create the regular melee units upon game start.

Keep in mind that doing this will no longer make it a melee map. If your aim is to make it so that you make a melee map like the ones that came with the game, but not need to place the units first, then i am not sure how you do that. I think you will have to mess around with JASS or some kind of advanced programming language to get that to work.

Hope that helps!