Go to Admin → Plugins → Email Service Providers, click Klaviyo, and select the green Activate button.
All API calls require the api_key parameter. You can find your API Key in the ConvertKit Account page.
After you click Connect, click on the enabled plugin again and then click on the Blue Edit icon
On the right side of the page you will need to route your Checkout ChampCampaign(s) to the ConvertKit List you created inside your ConvertKit account.
Click on the Green Route + icon and use the drop-down options to route your Checkout Champ Campaign(s) to the ConvertKit List then select Create.