First of all activate Advertising service. Go to the Services view (Window > General > Services) and make sure that the Ads service is enabled. If no, follow the steps in the view to get it enabled.

The next step is to activate and to setup implementation code. Go to the Dashboard and click to Integrations tab. Here you need to add UnityAds integration element. Use context menu to do this. If there is already UnityAds integration, you can remove it or just modify it.

Now you need to get you App and Ad Keys. You can do this in the Unity Services Dashboard.

Here create App Keys for each platform you are going to use. And Ad Keys for each platform and ad type you need.

Also select all the necessary ad formats you want to use in the Type Mask field.

The last step is to save changes. Click on the floppy disk icon in the right top corner of the Dashboard.

These are all manipulations that you need to do to get the UnityAds service work.

Read more information about ads usage in the project in the next topic:

How Ads Works