akshit in "home designer" you can just snap objects in a room. If you need to make holes in the walls to have real doors and windows, please have a look at "floor map designer" compatible with "home designer" 😉
Yes the project can run on WebGL, but maybe some parts of the code are using dependencies like System.IO.File that have not been surrounded by #if UNITY_DESKTOP, so it should not be too long to fix. I can have a look if you are still stuck there let me know!