Top panel:
Faders for 4 channels with mute button below each
To the right of the faders, the column of vertical buttons are FX presets numbered 1 through 6 from the top downward. You can customize these and save them using the GoXLR on Linux utility.
Then there's a slight gap below, and 3 more buttons arranged vertically again, those are sample banks A, B and C.
Top nearing the right, the 4 knobs arranged in a square are:
Reverb top left
Echo bottom left
Pitch top right
Gender bottom right
Below the knobs are four sample pad buttons arranged like the edges of a square frame. The Clear button is in the middle of them.
The column of larger buttons down the right side from top downward are to enable/disable FX:
Megaphone
Robot
Hard Tune
FX
Another slight gap below, then
Censor (plays 1K Tone and overrides mic when held down)
Mic Mute (mutes when held down, unmutes when you let go). That behaviour can be modified in the GoXLR Utility.

Back panel connections from left to right if you're looking over the top:
DC in
Optical in
USB
Kensington lock slot
Line Out minijack
Phones minijack
Mic minijack
Line-in minijack
XLR mic