How to add footprint parameter into ODATA API query?

I just read FAQ about OData API:

And now I am able to make such querry:$format=json&$filter=startswith(Name,'S2') and ContentDate/Start ge datetime'2018-08-25T00:00:00' and ContentDate/End le datetime'2018-08-26T00:00:00'

But I still don’t understand how to add footprint search parameter into this query.
Could you help me please?
Add any point and polygon parameters in my query example.

The page says

ContentGeometry footprint polygon coordinates in GML format.

But I’d suggest you ask for help at Open Access Hub (which is not related to Sentinel Hub).