What this page is
Connect or disconnect the Google Ads account.
Open Overview in Your Brand, then Account in the panel list beside it. It has its own address, /ads/account, so it can be bookmarked or sent to somebody directly rather than described as a series of clicks.
A look at it
A walkthrough of this screen — what is on it and what each control does — is being written. Until then the page itself is one click away.
Account
/ads/account