The subpane for any modifier does not appear in my version of Blender I am new and novice at Blender (version 2.79 under Mac OS 10.11.6 El Capitan).
I am just trying to intersect a cube and a cylinder. I get them to overlap, select the cylinder then I hit the spacebar to get to Add modifier. I select Boolean and ...nothing happens.
No subpanel with information or asking to click on the cube. Nowhere to decide what boolean operation to perform. 

I lost half a day looking on line for tutorials, but got nowhere. I suspect this is a bug.
Can anyone help me ?
Thank you
Alain
Your Modifier properties will be under this tab.