To illustrate combat, I have experienced some and landed on a variant where you can move your own players on the map.
When I post a combat map, whoever posts first will move their player and HIT ENTER.
When you have done this, the map will update/be saved and a new URL is created.
COPYPASTE this new URL in your post as a map update. The next player will then use this updated map and move his/her character, repeating the process.