There are two ways to post Content:
Live Posting: Content goes live straight away. This can be achieved by selecting the "Send Now" option in the send menu and pressing the green button labeled SEND. The content will go directly to your story at that point.
Scheduling: Content is assigned to a storyboard, which is sent out at a scheduled time as decided by yourself. You can schedule a piece of content by selecting "Schedule for Later" in the send menu. Then you'll need to either create a new scheduled storyboard or add to an already existing storyboard (both options are in the send menu). Press the green button labeled SCHEDULE to confirm. Content will appear on your story and be published in the order that you upload them.