Google ad manager help

Hello. Please, can someone help me with setting up google ad manager to display ad blocks? How do I create an ad block in google ad mamager, configure it and link it to the desired application? I tried to search for information, but apart from the Google documentation, I didn’t find anything, but their documentation is unclear to me, then I tried to do something myself, I created the placement, created the blocks I needed, it says that the blocks are active, but there is no advertising in the application.

Show your blocks and any error messages you getting.