Coordination with Other Traffic at Unattended Fields

Self-announce is passive. You broadcast, but you may not get a response. What if another aircraft is also at the field? How do you coordinate?
The answer is listening discipline. You monitor the frequency continuously. If you hear another aircraft, you know its position and intentions from its broadcasts. You decide your own actions to avoid conflict.
For example: you are inbound and hear "Feldkirchen Traffic, D-EFGH, on final runway 09." You are 10 miles out on initial approach. Your natural next action is to orbit or extend downwind to allow D-EFGH to land first. You do not need clearance. You use judgment.
If you hear "Feldkirchen Traffic, D-EFGH, holding point runway 09, ready for departure," and you are on downwind, you may decide to slow down and land first, or to abort your approach and go around, or (if you are still far out) to orbit. Again, judgment.
This is self-regulation. There is no controller to separate you. You look outside, listen on the radio, and make safe decisions.