I think you should try this one first to practice.

http://elouai.com/new-room-maker/index.php

All you do is click on what you want to add. Like if you want to change the color of the walls, click on "Walls."

Then you will see all the different colors and designs. Click on what you want and it will change the room.

If you want to add chairs click on "Chairs", then pick the chair you want by clicking on it.

It will automatically go to the room. Then, to move it where you want it, click on it, hold your finger down on the mouse and drag it to where you want the chair to go, then let go.