It's very simple, just a matter of connecting a few visual programming blocks together. Essentially every connected input device's axes and buttons shows up. It's trivial to add chording and multiple-press actions as well.

@mushycraft
I just installed ControllerMate... it detects my 3dconnexion and i put some controllerBlocks to a new page. ControllerBlock for the axis gave a feedback in ControllerMate but the ControllerBlock for the buttons don't respond to a click...??
am i doing something wrong?

Make sure you're using the blocks for the individual buttons, and not the one for the button group (though if you go into the options for that one you can make it work too).