First of all, identify and locate the carpet. There must be one in the living room, one in the entrée and maybe one in the bed room. You are lucky if you have less than this. Search for stains that will make your mother crazy. Try to cover them, but avoid any attempts to clean any stain. There are professional carpet cleaning London services that will deal with all spots and leave no traces.
Next step, when you know where the carpet is, sweep the carpet. Be careful with residues on the floor. Do not spread any fresh stains. Before vacuuming, your carpet must be free of trash, bottles, plastic cups, old newspapers and magazines. Only then you can go the the next level.
Vacuuming is the easiest way to deal with dust and smaller dirt particles. Be careful to clean the vacuuming machine before starting, it can blow off dust and further complicate the carpet cleaning. Clean with direction. Start from the window to the door. Do not forget to clean under and behind the furniture. Clean the upholstery inside out.
Go to the bedroom. You spend from 3-8 hours a day there, so it should be clean and comfortable enough. I bet there is a fair amount of dust under the bed and you mattress has changed colour. It is smarter to air the room and wash your bed linen at least twice a month in order to avoid breathing or skin irritation.