ᐅ Elevation Floor Plan Garage. Interpretation of the submitted design

Hello everyone,

I know this is a rather basic question, but could someone tell me how many centimeters I need to go down from the street level for the garage?

I was planning to have an excavator come on Saturday to roughly dig out the garage area.

I would also appreciate your opinions on how you would design the slope in the end.

Also, how many centimeters of frost-resistant material should be installed? How much gravel? And how thick should the slab be? The garage will be 7 x 7 meters (23 x 23 feet) with 24 cm (9.5 inches) masonry walls.

Thank you very much for your help.