How do I track which Google/Linkedin Campaign resulted into Backstage sale

How do I track which Google/Linkedin Campaign resulted into Backstage sale

I have Google/Linkedin Campaigns going to drive traffic to our events page - https://events.culytics.com/2020Summit

I have Google Analytics turned on. However, the URL does not change when people go through the sales process. How do I track which campaign results in the sales?

Thanks