How do I place Random Groups in my maps?
Open up the editor.
At the top menu part select Layer:
Layer is divided into the following groups:
T = Terrain
D = Doodads
U = Units
R = Regions
M = Cameras
In future all you have to do is hit one of those letters on your keyboard.
Select Units or hit U on your keyboard.
This will open a mini-window within editor - it will be titled Tool Pallet.
In the image attached below you will see my desktop, I opened up the editor and I opened up four tool pallets.
1. Terrain Pallet where you can modify all of the terrain stuff.
2. Unit Pallet - where it is set for Team 1 (Red) you can see all of the units
3. I scrolled down to Neutral Hostile units - Currently it is set for the Tile Set Barrens (where it says Barrens) You can select any tile set you have through that and get different creep pallets.
4. Is doodads since I assume you know what that is.
You can only plop down one unit at a time. Not a group like with doodads.
You will note that they are arraigned in groups for instance the Barrens tile set for neutral hostile units starts off with the group Centaurs, followed by Bronze Dragons, Followed by Harpies, etcetera so on and so forth.
Creative placement can consist of either a nook or a gully as in my Spiders Den (second image) or you can place a village of creeps together as I did in Troll Village(third image).
Mind I took the time to make torch units and fire-pit units, I also enlarged and changed the pathing and names of the log structures - all of those are now neutral hostile and when the player reaches the village s/he will be able to attack not only the living units (trolls) but the troll village itself clearing out the area of log-hovels and fire-pits and torches.
Whereas the spider's den has a gold mine (those steep hills are pathing blocked by the way, no cliffs please) the troll village is only there to give the player something to hone their skills and experience level on.
A couple others are attached to give you an idea of how to place creeps nicely in a map.