I want to design a small bedroom using items from online stores, online for free. Can anyone help me?

I will be moving by late February mid March into a new house and i want to basically map out my new room and i know the measurements and the items i want but i dont know if theyll fit! p.s. im a tech guy im a gamer(xbox 360, have a study station for my laptop and schoolwork) Basically i need space for my bed desk and entertainment part or the room S.M.L (SAVE MY LIFE)!