Please be advised that you can make rounding only for containers and structures.
Let's see how we can add border radius to the container via editor tools:
1. So first of all, select any block and go one step higher to the container.
2. After that set the background image or background color (if necessary) and the rounding.
Please note, when you add an image block to the container, rounding won't work because the image will replace this container.
Now let's see how we can add border-radius to the structure:
1. Select the desired structure and set the background image or background color (if necessary)
2. Perform the rounding
By the way, you can set the separate rounding for different sides
If you have any questions, please email us at firstname.lastname@example.org.
Have a great day:)