It starts with the commander at the end of the tail of long crater, his ship having crashed. Making his way down the crater (the sides too steep to exit), encountering enemies and acquiring units in sequence (glaive, rocko, warrior) in order to teach basic counter mechanics (riot < raider < skirmisher < riot). Along the way he also gathers reclaim. At the end of the crater, he finds his ship and an exit to the crater. At the top of the crater, he finds a factory which he can use reclaim to produce units from (no metal spots). His objective then becomes to take out the AA tower that shot him down, which is on the hill at the bottom of the asteroid.
I've made a rough heightmap (Its detail and slope heights might not be perfect).

It should be about 12x12 to fit the units in properly.
Ideally, it should look fairly good (being an introduction to the game) and have the dark black areas on the outside be a starfield. Though even a simple map would at least allow me to make the mission functionally, so i'd appreciate any help.