First of all, it is necessary to define global parameters in the program. You can open the list of global parameters by using the menu Edit → Global Parameters.
Define two parameters – one for the position of Node 5 on the top chord (Xtop) and one for the position of Node 6 on the bottom chord (Xbottom). Since the variables define the distance between the member node and the start/end point of the member, select the "Lengths" unit group. The parameters are initially defined as values. Therefore, select "Value" in the "Definition Type" list. Define the value of both parameters as 0.
