The Metaparameter Explorer allows you to calibrate a variable using an expression. For example, if you want to calibrate a link variable, you can specify this in the Metaparameter Explorer, and then assign it a value using the Function manager.
Suppose you want to calibrate the storage routing exponent (m) on one of the reaches in a Source model. Initially, idenitfy which link in the model you want to place the expression in. Then, use the Metaparameter Explorer to allocate a parameter to the variable (steps outlined in Figure 1).
Figure 1. Calibration Wizard (Metaparameter Explorer)
Finally, to define the value of the variable, m in the Function manager, choose View » Expression List... to open the Expression List Viewer (Figure 2). Click on the hyperlink (circled in orange) to open the Expression Editor and set the value of m to 2.
Figure 2. Expression List Viewer (Metaparameter Explorer)