The five things to do before your first send: inbox, people, emails, first send, warmup.
The "Get started" meter in the bottom-left tracks your progress. Click it any time to jump back to the checklist.
Step 4 — click "Go to Message Center" once contacts are in a sequence to approve the first send.
Step 5 — "Warm up your inbox" builds sender reputation on a new inbox before you send cold. It is ticked once warmup is running.