Can anyone help me? Trying to make animation in/out points adjustable in essential graphics

As the title says, I am using essential graphics to make a mogrt template for lower thirds.

I’d like the option to include baked-in start/end animations, so when it is used in premier, the user can just drag the clip (as employed by other Adobe stock essential graphics)

Can anyone provide me insight, expression or a tutorial to help? Can’t seem to find exactly what I’m looking for online.

Thanks