You will need Organization Core Id, Game Id and Reporting API Key to integrate Unity Ads.
Go to Dashboard and click Settings in the left menu, you will find Organization Core Id in organization settings:
Go to Ads Data Export -> API access in the left menu next and create new Monetization Stats API Access key, this is your Reporting API Key:
Go to Projects -> Select your projects and click Settings -> Project settings in the left menu, you will find Game ID for corresponding platform here:
Now just copy these fields into devtodev settings and enable integration: