I can't run the ADMOB ad

My problem is that no ads are running, does anyone know how to place the ADMOB ad?

Please show your relevant blocks so we might assist you more effectively.

I had deleted it, but I wanted an ad and a banner to appear when it started, and an ad for a prize when a button was clicked.

I tried to redo it as it was, but I don’t remember. I know I tried in several ways. Please can you help me do a very basic one?

I have already entered the application ID and the ID of each ad, I am using the test ID