1) Start by placing this family in your project at the exterior of your building. If your project is in the Northern Hemisphere orient this family to be South facing (North facing if in the Southern Hemisphere). You can rotate the orientation, in plan, up to 20 degrees East or West without significantly impacting the efficiency of the thermal mass. 2) Next, determine your project’s latitude. This family comes with latitudes 36-48 provided. The latitude can be North or South. These latitudes are provided because they are the most likely range where passively heating a space via a thermal mass would occur. 3) Next, determine the Average Winter Outdoor Temperature for your project's location. This can be found by doing a search on the internet. This family provides for temperatures from 20-45 degrees F. 4) Next, you choose the thickness of the thermal mass. In this family, because it is concrete, you have the option of 6in, 8in, 10in, or 12in. The more mass you have then the less wall surface area will be required. 5) Determine the floor area of the space which will draw heat from the thermal mass, and input this number into the properties. 6) To accurately reflect how much wall surface area and thermal mass thickness is required for your space, you will need to adjust the height and length of the family until the parameter 'Wall to Floor Ratio Check' equals zero. Once this parameter equals zero you will have determined the appropriate size of thermal mass required for your project.