Sit with the child next to you. Montessori lessons should be demonstrated by the instructor before the student begins using them on his own. Make sure you demonstrate and discuss the lesson in a calm, low tone and that the student can view everything you do clearly.
Place a square of white paper under the frame. Make sure the student sees that the square fits exactly, so that no white paper is showing. At this point, the inset should not be in the frame, so you will both be able to see the white paper in the empty shape.
Trace around the shape using the inside of the frame as a guide. Use any color pencil that you like.
Remove the frame so that the child can clearly see your resulting shape. If you wish, you can talk about what shape it is. The most important thing is that the child understands how the shape got there (by tracing the empty frame with the pencil).
Fill in a small part of the shape with a different colored pencil, using parallel lines. These lines should be as straight and even as possible.
Invite the child to try filling in the shape. Encourage her to use the same type of lines you were using, and give her your pencil. If the child has difficulty emulating your lines, encourage her and demonstrate exactly how you held the pencil and moved it so that your lines were straight and even.
Allow the child to practice the exercise alone, using any frame and colors he likes. As he repeats the process, he will gain more control of his hand muscles, and also develop an eye for color. This will help later with correct handwriting and artistic efforts, as well as with shape familiarity.