Click on Parameters tab for the calculation you want to connect to a Report Parameter
Click on the 
Filter
Helper button
Select Report Parameters | name of the parameter you want to connect
When you create Report Parameters for your Layout, you may want to connect the Report Parameter to a calculation input:
Click on Parameters tab for the calculation you want to connect to a Report Parameter
Click on the Filter
Helper button
Select Report Parameters | name of the parameter you want to connect
Once a Report Parameter is connected, when the user changes the value of the parameter, the calculation parameter will change as well. This is useful for example in the Period Amounts, you could hook up a Parameter called "Period" to the "End Period" of that calculation.