After creating a campaign, you would be directed to the Prospects page.
Step 1: Click on Add Manually button
Step 2: In the form that appears, in the first column, type in the prospect’s email address (required). Fill in the rest of the details about the prospect.
Step 3: Click on the List. (You can select an existing list that is already there or type in a new list name to add this prospect to a new list)
Step 4: Click on Save Prospect.