GTag event for Sign Up with reference to Ad (Utm Variables?)

I created a Facebook ad with a link to a page on my website:

https://www.example.net/signup?utm_source=facebook&utm_medium=cpc&utm_campaign=launch

With the UTM variables I can track which campaigns the user came from.

I also need to know how many users really signed up so I am trying to use GTag to create an event:

gtag('event', 'sign_up', {
  'event_category': <category>,
  'event_label': <label>,
  'value': <value>
});

How to relate this event with the Facebook campaign defined in the UTM variables?

Solution

If the user lands on the website from that link with the UTM parameters and completes the desired action (sign_up), Google Analytics will be able to understand for itself if that action is associated with that campaign.

If you set a goal in the view so that it activates when an event has action sign_up, you will conveniently see in the channel report the number of goals associated with that specific source / medium.