Hi pixiedixie

You can use the curved wall tool (5th icon in the floor tab)--> as it opens, you will see wall length option, just write the desired dimension (window + frame). You don't need to complete 180° or 360°, just draw the segment you need

After you create the walls--> properties bar (left of the screen) --> set the desired height (don't forget to press Enter in your keyboard after each change in the properties bar). Also, set the elevation (elevation slider, etc)

Patricia