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 few demonstrations.
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.