If you wish to change this, you can do so at the point of opening TRAKTOR, or at any point
by disconnecting, 
and subsequently reconnecting the device's USB connection on the rear
panel.
Deck Setup Options
There are four use cases (or Deck Setup combinations) for how the X1 can be setup to control
TRAKTOR's four available decks:
▪ Decks A & B (default)
▪ Decks C & D
▪ Decks C & A
▪ Decks B & D
In all of the above combinations: The first Deck of these potential combinations will always
be situated on the left-hand side of the X1, whilst the second will always be assigned to the
right-hand  side 
of  the  X1.  Using  the  example  of  the  default  Deck  combination  (A  &  B),
Deck A will be controlled by the left-hand side of the X1, Deck B by the right-hand side.
3.3 Using the X1 to Browse & Load Tracks
 
The 
process 
of  browsing  through  and  loading  of  tracks,  takes  place  in  the  central  section  of
your X1 device.
The BROWSE encoder, SHIFT, Load Left & Load Right buttons.
Follow the 
below instructions to understand how to use the X1 to browse, navigate, and load
tracks in TRAKTOR.
Key functions when using the X1 with TRAKTOR
Using the X1 to Browse & Load Tracks
 
Traktor Kontrol X1 Mk2 - Manual - 13