Trigger_auto is a simple point entity which will trigger in the first server frame, right after the map has loaded. Because some entities still set themselves up properly in the first server frame, it is advised to set a little delay of about 0.5 seconds, so trigger_auto does fire in a later frame and no unwanted behaviour is exhibited.
Target target : Entity to trigger on map start. Trigger use-type is defined in "Trigger State" keyvalue.
Delay Before Trigger delay : Delay before trigger entity specified in "Target".
Kill Target killtarget : Entity to remove on map start.
Global State to Read globalstate : Reads a global state variable (from env_global) to use as use-type/trigger-state.
Trigger State triggerstate : Changes trigger use-type in which target will be triggered.
1 : Remove On fire : Remove this entity when it's done triggering. This should be always selected due to performance reasons.