Prima's Official Strategy Guide
Types of Triggers
"The default is None, but you can create some special triggers. End #1, #2, and so forth are used for ending the mission. You can create seven possible endings for each mission - six are numbered and have their own debriefings and continues in case the mission is in a capaign. If you have more triggers of eachspecified type (such as multiple triggers with End 1), all of them must be activated to end the mission.
Loose is a speciel type of ending; there is no debrief after this end(only mission statistics), and if you set multiple loose triggers, the mission ends when any one of them is activated. This usually used for a Mission Failed ending.
Switch is another important trigger type. When this trigger is synchronized with a waypoint, it forces groups to move to the next waypoint reguardless of other conditions. This means all remainingwaypoints between the actual and switched ones are skipped. For example, you have a truck with five Move waypoints, and there is a Switch trigger synchronized with the third waypoint of the truck. At the beginning of the mission, the truck goes to the first waypoint. When it gets there it continues to the second, then to the third. The truck then waits there for the activation of the trigger before continuing on to the fourth waypoint - it works the same as a normal trigger. But if the trigger is activated while the truck is moving to the second waypoint, the truck immediatly changes its route and heads to the fourth waypoint. If the trigger is set to repeatedly and is activated again when the truck moves from the fourth waypoint to the last one, the truck returns to the fourth waypoint even if the waypoint was already completed.
The last special trigger is the Guarded By type. Specify positions on the map with these triggers. For example, set triggers around all cities on the Soviet part of an island as Guarded By East. Then create a few units with the Guard Waypoints. Although these units guard the entire area, they prefer areas within the triggers and check these locations often, attacking anything they see.
Within the Type area, you can also insert text. This appears in the mission editor. It is also used for Radio triggers and appears in the Command menu.
NOTE
The condition and effects menus allow you to program special actions when a trigger is activated. This includes sounds, music, and even cutscenes."
There, that's what that guide says about triggers, that was alot of typing, hope it helps ya.