ION Radiant Basics
Any good QERadiant tutorial is going to be your best bet for learning ION Radiant, but to get you started here are a few handy controls. Naturally all of these can be reassigned in the settings files.
mouse drag -- creates brush click -- selects an item esc -- deselects all selected items space -- duplicates a brush arrow keys -- move camera a/z -- tilts camera up and down d/c -- lifts / drops camera ctrl + middle button -- summons camera to that spot [] -- change gridsize n -- entity info s -- surface inspector insert/delete -- zoom grid in and out. tab -- changes perspective of XY window.