One point interior begins with the horizon line/eye level. Place a dot near the center on this line. The dot represents the central vanishing point. All receding parallel lines will head towards this dot.

Draw a rectangle some where around this dot. This rectangle will represent the back wall when complete. Using the CVP as a guide draw lines from the four corners of your rectangle outward. (Remember to make sure your lines go from the CVP to the corner and away, as in outward.) You now have a room with a floor, ceiling, left wall, right wall and back wall.

Now it is time to create an entry door. Draw a line up the side wall. Make sure the line goes above eye level if you are standing in the room and should be able to pass through the door without crouching. Now draw a line that passes from the CVP to the top of your door line and away. Using this line as a guide you can now create the top and other side of the door.

Using the same method on the opposing wall create a window.

Now it is time to create a rug. Add fringe is you like.

A more complex object would be a table. Notice that the horizontal lines are all horizontal and the vertical lines are all vertical. Only the receding lines that are parallel converge to the vanishing point. If similar areas are the same size on a horizontal line then the measurement can be carried across the horizontal line. Notice the red lines that show a similar measurement.

On your drawing consider creating a chair or other furniture.