Reading alone does not provide enough information. They will require verbal instructions for less complex steps. For more complex steps requiring problem solving, they will require a demonstration.
In order to form the correct mental image of what they need to do to arrange the triangles on the fabric and Heat n' Bond materials, they will require a few demonstrations.
The person can follow a demonstration of cutting a triangle piece using the template, pealing the paper backing on the Heat n' Bond and ironing the pieces into place.