The prerequisite for using the Facebook conversion tracking is to have already installed your Facebook Pixel ID correctly to your event.
If you have not installed your Facebook Pixel to your event then to use conversion tracking you must first follow our help article 'How do I set up my Facebook Pixel for Facebook Ads?', otherwise, if you have your Facebook Pixel installed correctly already then you are ready to move forward.
Moving forward from the previous step the rest of the magic happens within your Facebook Ads Manager.
All ads that are running + any new ads that are created need to have the Pixel enabled manually. This happens on the ad level (not the campaign or adset level). It's slightly hard to find but it's this grey switch down the bottom of the single ad editor panel, it's called Pixel and when you click it the switch turns blue to tell you it's activated.
That last step is very important because that's the setting on every ad that decides whether that ad is counted and tracked with the Pixel. Once that's set correctly and the pixel is activated on the ads level as well then everything is working correctly and we wait a few days to a week to see the results of the ads you just activated the Pixel for.
After you have done all of the above and waited a few days to a week for data collection, if the ads manager doesn't already show you how many sales the ads made then the column can be added manually with the profiles dropdown in the Facebook Ads Manager.
Usually, by default it's set to Performance or Engagement and it sits slightly to the right and above the table of campaign/adset/ads data. When you click that dropdown it gives you the option to Customize Columns (click that). The 2 main fields you'll be interested to add to your custom reporting profile are 'Website Purchase' and also 'Website Purchase Value'.
After you save that as a preset then you'll easily be able to reference how many sales your ads are making very easily and for any ad that has the pixel activated for.