It helps me a lot ... "Get off" = Remove yourself from on top of something - Get off the couch! - Get off the wet floor!
"Get out" = Leave a place - Let's get out of here. - Get out of my house!
You get in/get out of a private vehicle: - Get in the van! - Time to get out of the car. - Will you stop playing around and get in the truck?
You get on/off public transportation: - It took way too long to get off the plane. - Get on the bus before it pulls away. - We will get off the train at the next station. - We need to get on the subway before 11:00.
For more help, see this; https://english.stackexchange.com/questions/333415/what-is-difference-between-get-off-and-get-out-of