What confuses me most here, is that you are asuming that this is an event. The set animation from is an action. Depending on where you call the action, it will do that only once, or many times.
So for example, if you want to do it when the game launches, uses the "on start of layout" event, and call "set animation frame" there. If you want to do it when a another event happens, for example the player dies, do it in the event where the player dies, for example, the same event where you set the health to 0.
Or, you just do it on every tick and use the trigger only once while true condition. But that's not what I would recommend