Once you create your campaign, tick the Go-Live button to send. Additionally there are a few others way you can send your campaign:
Schedule: Use the schedule button to set when your campaign will be sent.
Send Communication: The send communication button at the top of the page will allow you to select an existing Live campaign and add recipients. Add one recipient for a quick send or add multiple.
Add Recipients: Use the add Recipients to a Draft or Live Campaign from the Recipients menu
Send button: On each template a Send option is given. This will allow you pre-select that template, add a campaign name and complete the remaining steps for creating a campaign.