You see beat phase of the song playing in Deck A on the Play/Pause button of Deck B so it helps you to hit it and beatmatch at the right time and vice versa.

Folder button glows when Deck A is loaded and Files button glows when Deck B is loaded.

Made this using all the good from the original mapping and mapping by DJ Efimov

You'll figure out by yourself all the mapping by playing around, here are some for more flexibility than the original mapping on the Hercules website.

Up/Down arrow keys -> Playlist Browsing Step by Step
Folder button + Up/Down arrow keys -> Folder Browsing Step by Step
Folder button + Files button -> Expand/Collapse Folder
Folder button + Jog Wheel A -> Folder Browsing
Files button + Jog Wheel B -> Playlist Browsing
Vinyl + Files button -> Expand files window
Vinyl + Pitchstick -> Adjust fine Tempo
Vinyl + Sync -> Reset to original Tempo of corresponding track
[<<] / [>>] -> Backward or Forward 8 beats
[-] / [+] (under Pitchstick) -> Decrement/Increment Dry/Wet for corresponding FX Unit
Vinyl + Button 1 -> Select/Set Hotcue 5
Vinyl + Button 2 -> Select/Set Hotcue 6
Vinyl + Button 3 -> Select/Set Hotcue 7
Vinyl + Button 4 -> Select/Set Hotcue 8

In Loop Mode =
Button 1 -> Loop Size -
Button 2 -> Loop Size +
Button 3 -> Loop Set In/Out
Button 4 -> Emergency 4 Beat Loop In/Out

In FX Mode =
Button 1 -> Effect 1 ON on corresponding FX Unit
Button 2 -> Effect 2 ON on corresponding FX Unit
Button 3 -> Effect 3 ON on corresponding FX Unit
Button 1 + Treble -> Effect 1 Amount on corresponding FX Unit
Button 2 + Mid -> Effect 2 Amount on corresponding FX Unit
Button 3 + Low -> Effect 3 Amount on corresponding FX Unit

Vinyl + [<<] / [>>] -> Effect Unit 1/2 ON/OFF on corresponding deck
Vinyl + Low -> Filter ON/Adjust for corresponding deck
Vinyl + Load A -> Unload deck A
Vinyl + Load B -> Unload deck B
Vinyl + Left Monitor Cue -> Flux Mode ON/OFF for deck A
Vinyl + Right Monitor Cue -> Flux Mode ON/OFF for deck B
Vinyl + Treble -> Auto Gain adjust for corresponding deck