Getting to the Text Editor
Clicking on the bottom right menu button will bring up a modal:
Write ✍️ link to open up the editor window.
Once on the editor screen, you can enter text as you would any other text area:
Here, my spelling is corrected with a red highlight on the word 'fow`. Entering text is as easy as deleting the placeholder text and entering something.
Toolbar for Easy Editing and Viewing
There is a toolbar on top of the markdown editor, in case you don't want to write all in markdown (why wouldn't you?). You can go fullscreen as well as split screen to view your rendered markdown:
It's a simple as that.