We understand that sometimes you met a contact at a networking group, are aware of a project, were referred to the contact, or have another reason to send a custom email 1 instead of the standard email 1 of the campaign.
This is easy. Just add the contact and click the Send Custom Email 1 checkbox to the right of the contact's details. After you add the contact, a generic dialog box will be presented and you can type your custom email. If the contact replies, Great-just use a reply action. If they do not, they will be scheduled for email 2 just like any other contact.