When you have a draft ready, you will see three dots next to the publish option on the top right next to your profile pic. Click the dots and you will see the ‘add to publication’ option, click on that and then you should see The Rabbit Is In as one of the options. Click on that and you are done.
So that was for drafts, if you have a post that’s already published on your profile, click edit first and then proceed as described above.
Let me know if you experience any problems.