All Active Campaign plugin tutorials:
1. Get your API Key and API Url this way
2. Then go to your stealthseminar account, and go to marketing plugins by clicking on your gravatar
3. Go to ActiveCampaign on the same page and click on connect. Then add your own API key and API Url in the corresponding input fields and hit connect.
4. Now you can go back to your event and click on plugins. You will now see ActiveCampaign there.