Need help with a ground level deck...

I am looking into building a ground level L-shaped deck, roughly 12 x

1. Needs to be low as the bulkhead is right in the middle on the plan, and the access to the cellar must remain.

I recently decontrcuted a sandbox that was on my property that was 8 x

I want to anchor these beams into the ground, but not sure how to do this. 2 foot dep holes and quick dry cement?

Also, as the deck will be about 6 inches high, do I have to remove the grass underneath, or will it just turn brown and die?

Thoughts are appreciated.

Bluesman