The Home tab in Creator Studio defaults to your Facebook Business Page(s), but you can check to make sure based on the highlighted icon in the bar at the top of the page. If you see the Facebook icon highlight and the bar is blue, then you are in the Facebook section.
From here you can start a new post in a few different ways, including:
Depending on which format you choose, the related composer will appear and walk you through the post.
If you wish to save, schedule or backdate a post, first go through the initial steps to compose a post, but stop before clicking Publish and instead click the arrow next to “Publish” to pick the option of your choice.