Congratulations on uploaded your lists and being ready to send your first email campaign! These are huge milestones for new users like yourself. The good news we were able to determine why you couldn't select your contact lists on your scheduling page. Your account is still under our Trial Period. During these trials, an account can only send emails up to 100 contacts. Both of your contact lists are well over 100 contacts. Because of this you will have to upgrade to a paid account to send your email to the full list. In fact, there should have been a messaging on your scheduling page telling you this with a link to upgrade your account to send unlimited emails.
Do you see this messaging on your scheduling page?