Marketing is where you plan content, schedule and publish it to your social accounts, and see how it performed.
Accounts are not connected here. They are connected in Technology, and Marketing publishes to whatever is connected.
The tabs
Strategy — who you are talking to and what you are trying to say.
Brand Playbook — your tone, voice and visual rules, so generated content sounds like you rather than generic.
Campaign Builder — a set of posts built around one push, rather than one post at a time.
Content Plan — the longer arc: what you intend to publish over the coming weeks.
Calendar — what is scheduled and when, and where you move or reschedule things.
Media Library — the images and video available to posts.
Performance — what actually happened after publishing.
Help — quick guidance without leaving the tab.
When a post fails
A failed post shows which platform rejected it and why. Most failures are a connection problem rather than anything wrong with the post, and the fix is in Technology, not here — reconnect the account and publish again.