In Ads Editor you control Google Ads conversions in two places:

  1. When CREATING the campaign (Google Ads, "Create campaign" button), in step 2 (Conversion) you choose a conversion that already exists in the account or create a new one right there. When you create one, Ads Editor gives you the TAG (global site tag + event snippet) to install on your site so the conversion can start counting.
  1. Once the campaign exists, each campaign has the "Campaign conversion" action (target icon next to the campaign name in Google Ads).

There you switch between "Use account goals" (the campaign follows the conversions of the entire account) and "Conversions specific to this campaign" (you select only the conversions this campaign should optimize).

Important rule: a "Maximize conversions" campaign in an account with NO active conversion can be created, but it will NOT optimize (no signal), so create and install the conversion first. A "Maximize clicks" campaign doesn't need any conversion.