Hopefully this tutorial will explain the most important parts of the radiant program to get you started on your 1st map.

Hotkeys: (Important keys are in bold)

Escape [Finish/Cancel selection]
Right Click [Move Across Grid]
Shift+Left click [Selects brush]
Shift+Control+Left Click [Selects Face]
Backspace [Deletes brush/entity]
Space Bar [Clones brush/entity]
T [Opens the texture tab]
Y [Patch editing options]
O [Opens the console tab]
P [Opens the preferences]
S [Opens surface inspector]
F [Opens your filters]
G [Opens your groups]
K [Colour selection]
X [Uses the clip tool]
V [Uses the vertex tool]
N [Opens the entities tab]
M [Gives map information]

Buttons: (Left to right)



x-axis flip [Flips on the X axis]
x-axis rotate [Rotates on the X axis]
y-axis flip [Flips on the Y axis]
y-axis rotate [Rotates on the Y axis]
z-axis flip [Flips on the Z axis]
z-axis rotate [Rotates on the Z axis]



CSG subtract [The CoD equivelent of carve - DO NOT USE THIS]
CSG merge [Combine 2 brushes into one - A real timesaver]
Hollow [Hollows your brush to the amount your grid size is set to]

Alt options:

Selection - Select - Select Complete Tall [Selects every brush in your current brush]
Grid - Grid # [Sets your grid size to # units]
Textures - (from austria downwards) [Selects that group of textures - press T to use]
Brush - # sided [Creates a brush with # sides]
Patch - Simple terrain patch [Create a patch of terrain] (will be explained in a different tut)

Camera Controls:

Right Click [Move forward / Move backward / Turn left / Turn right]
Control+Right Click [Move up / Move down]
A [Look up]
Z [Look down]

Tabs:

Texture tab (T) [Displays all the textures in the group you select]



Entity tab (N) [Displays the tab to enter entity information]



Filters tab (F) [Displays texture filters as to which are shown in-editor or not]



Surface Inspector (S) [Adjusts the alignment / sizing of textures on faces/brushes]



I hope this gives you a rough guide as to what a few things are.