As a teacher, the 'Create a new section' pop-up will show you LMS-related options dependent on the accounts you have linked to your Code.org account (Google for Google Classroom and Clever for Clever)

If, when you click to create a new section, you do not see a 'Clever' option, it's likely that your Code.org account is not linked to your Clever account.

To link your Clever account to your Code.org account, check out the steps in this article.

After linking your account to Clever, you will then see Clever as an option in the 'Create a new section' pop-up box.