Thanks!
You may have missed a few options then, at the "Legends" step. You can:
- click on keys to edit its text label (and also add text/icons or even custom SVG by clicking "vector")
- drag and drop icons from common icon libraries, from the "Icons" tab on the left panel
To edit your set to make those changes:
- Go to your creations using this link, or by clicking the user icon in the top right
- Click the set you want to edit
- Click the "customize" button
Note that it won't actually "edit" it, but create a new one. So you have to complete the process until "save for later", and update your code in your first comment :)