I've made four maps. One is balanced, three others are unbalanced.

1 - 2vs6 is an unbalanced map, you can play it with your buddy or with an AI against 6 players. Use multiplayer to set up teams.

2 - Resources is also an unbalanced map, you can play it with your buddy or with an AI against 6 players. Use multiplayer to set up teams.

3 - 5vs3 is also an unbalanced map, you can play it with a team of 3 players against a team of 5 players. Use multiplayer to set up teams.

4 - Iceland is a balanced map where you can play 2vs2vs2vs2 or just 4vs4 or even 2vs6. Don't try 2vs6 in impossible difficulty against AI, they will annihilate you in just 5 minutes. Use multiplayer to set up teams.

Note: Extract the contents of the .7z file into SDcard/rusted_warfare_map

Let me know if you liked them or any suggestion.

The maps didn't appear for when I logged into the game and checked "Your Maps".
And yes I added them to external sd card and put them in the folder for the maps

Have you unpacked it?

There was just a file that I got from the download

It works. You have to extract the .7z file contents into that folder. The "Maps.7z" file has 8 files inside it, 4 .tmx files and 4 .png images. When you open the SDCard/rusted_warfare_map folder you must see those 8 files inside that folder.

If you want to play the maps from the "single player" menu you must select "Your Maps(from SD card)". When playing multiplayer, after hosting a new game, change the "type" from the default skirmish to Custom Maps, then the maps will appear.

I used ES explorer to extract the files.

Change the folder name to this bellow:

SDCard/rusted_warfare_maps

I transferred them to the folder in sd with the other maps I downloaded already and the maps works good.