Step 1: Go to 'Integrations' and click 'Marketing Emails' on the right.

Step 2: Click on connect button next to 'Convertkit'. 

Step 3: Log in to your Convertkit account click on the top-right menu icon to navigate Settings.

Step 4: You'll notice tabs on the left of the settings page. Select the Advanced tab and copy your API Key and API secret.

Step 5: Now, go back to your sumopreneur account, and you will see a pop-up where you'll ask for Name and API key, & secret key

Give a name to your integration. 

And paste the API Keys you copied from Convertkit. Finally, click the updates button to connect the service.