Terrain Brush not working?

I just started using Tiled, and wanted to make a terrain brush. I’ve followed tutorials, and seen other questions such as this asked, with the answer being something along the lines of their corners not being right or something.

Well, nothing has worked for me so far. How does this work,and what am I doing wrong?

download a534dec6aa0e794cab600db6a3bff53a

edit: I think I know what I’m doing wrong.

Your terrain only has corners defined, but you’re drawing shapes consisting of things other than corners (vertical sides, horizontal sides, etc). You will need a tileset and terrain mark-up that covers all the situations that you will need to map, otherwise Tiled will get it wrong.

Edit: Whoops just noticed that you apparently already figured it out.
In the future, when you realise what you’re doing wrong, you should explain what it was in your post, so that people who have a similar issue in the future who find this post will also know what to do.