On the feed page, tap on the bottom right-hand corner where you'll find a circular icon with a pencil outline (it is orange).
After filling out your content, click on the “X” on the top right-hand corner. A pop up will provide you the option to discard or save.
Once it’s saved, you'll be directed back to the Feed page and whenever you are ready to return to your draft, click on the orange pencil and you'll be greeted by a pop-up asking if you want to continue your previous draft!
Please note that you are only able to save one draft at a time.