This tutorial will walk you through how to create what is commonly referred to as a "keyframe trick"

Keyframe tricks are required to use the vast majority of events in REDPF in Multiplayer.

NOTE: Keyframe tricks are NOT needed when mapping for Single Player RF.

Prerequisite knowledge: How to create basic movers using keyframes

1) Create a "Delay" event to use for your moving group. Please note that this doesn't have to be a delay event, and could be pretty much anything else in the editor that can be put into a moving group.
2) Create a group containing the "Delay" event, and keyframe that group.
3) Create a second keyframe within the same moving group, and move this keyframe away from the first one.
4) Go to the properties for each keyframe, and set the "Movement Type" to "Ping Pong Once", and "Departing Travel Time" and "Returning Travel Time" both to 0.00 seconds.
5) Select whatever event you're using the trick to activate, and note the object UID. To locate this, look at the REDPF console in the bottom left hand corner of the main REDPF window with the object selected.
6) Open the properties window of the second keyframe in your trick, and insert your event's UID into the "Trigger Event with UID" field.

Examples of where keyframe tricks are necessary:
-Creating a teleporter
-Toggling bolt emitters
-Toggling particle emitters
-Toggling fog
-Making an explosion (and/or geo crater) in your map
-Removing clutter objects when triggered

You can download an example keyframe trick below. This group contains the keyframe trick, a trigger door object to activate it, and an example event (shown in green) as a placeholder for any event you need to activate using the trick.
[Download Keyframe Trick Group]