Gladly there are some "how to design your own bedroom games" which can help you do the following in very few steps:
You can make some rough sketches using the art tools of the games. These tools do not require you to have even the basic designing and sketching skills, you need to drag and drop some items to make the sketch. If you have dimensions in your mind then you can put the figures in the input and the tools will help you create the sketch within the dimensions.
You can make a complete bedroom plan,apartment plan and house plan easily. The plan will show the measurement and dimension of each room, furthermore the plan can be turned into a 3d model. If you intend to use it for the real time construction and building project, you need to have a designer to review the plan first for flaws and mistakes.