I am having trouble attaching stairs to a deck. Note that my deck is not attached to any structure and I think my problem is that I have not specified the elevation for HD Pro to know how or where to connect them. I'm watching all the videos over & over, but still can't figure out what is needed to specify this dimension, so that my straight stairs or drawn stairs will automatically join my deck. Any advice would be very much appreciated. This software is very powerful, but it takes some time to become familiar with how all the parts effect each other.