In the Project window, click on the imported FBX object.
In the Inspector window, click on the Animation tab.
Set "Anim. Compression" to "Off".
Split the animation into four states in the "Clips" list: retracted, deploy, deployed, and retract.
The retracted and deployed states are a single frame.
You should prefix these states with the part name to avoid confusion if multiple parts of the mod contain animation.
Drop the part under model and unpack it completely.
In the Part folder, create an Animation Controller.
Double-click on the controller to open the Animator tab.
Drag the four states into the Animator tab.
Start with retracted so that it automatically links to Entry, then the other three.
In the Animator Parameters tab, create:
a boolean "isDeployed",
a trigger "reverseAnimStateChange",
a float "playbackMul" = 10.
Create the transitions between states.
Entry → retracted
retracted ↔︎ deploy
deploy → deployed
deployed ↔︎ retract
retract → retracted
Click on the transition from retracted to deploy:
set "Exit Time" to 0,
uncheck "Has Exit Time",
uncheck "Fixed Duration" (in Settings),
set "Transition Duration" to 0,
add the boolean "isDeployed" = True to the list of conditions,
check the animation by playing it in the preview window.
Perform the same operation on the transition from deployed to retract, except that "isDeployed" = False.
Click on the transition from deploy to retracted:
Set "Exit Time" to 0,
Set "Transition Duration" to 0,
Add the "reverseAnimStateChange" trigger to the list of conditions.
Perform the same operation on the transition from retract to deployed.
Click on the retracted state:
Add the "Module_Anim State Informer" module.
Perform the same operation on deployed.
Click on the transition from deploy to deployed:
Set "Exit Time" to 0.99,
Set "Transition Duration" to 0.01.
Perform the same operation on the transition from retract to retracted.
Click on each state and in "Speed" > "Multiplier", select "Parameter". It should automatically display "playbackMul" in the dropdown. This is for playing the animation ten times faster in the VAB.
On the mesh, add the "Animator" module and select the controller under "Controller".
On the root part, click "Add Component" > "Module_Deployable".