Ok. Me and UnevenElefant5 are working on a map, Enigma. It'll have a forerunner structure in it, which is supposed to be a training center for ancient forerunner fighters. We're planning to create a device_machine, like a door, which will activate when the player gets too close, and move a flat, fake, Flood combat form in front of him (like a practice target) similar to the fake Brutes on Halo 3 the Pit.

Where do I get started?

They made some of those popup Brutes for the H3MT maps, I guess your best bet would be to ask them.

Well first, you want the model and textures in 3ds max.

delete all frames and nodes.

Add 1 frame called "frame root"
link the model to the frame.

Make an animation 3ds max with 2 position frames.

Have:
0=default
1=Moved down somewhere below the default
2=Moved up to the default

So default should be when you see the object visible ingame.
Frame 1 should be somewhere so that you cant see it ingame.

The export the animation as "device position.JMO"
Export the model.

Compile the collision, model, and animations.

Make sure the node list checksums are the same in the animation tag and gbxmodel tag.

Setup a "device_machine" tag to however you want.

Place in scenario.
Compile.

Test ingame.