Removing and replacing the rear wheel on your Dash is a pretty straightforward job to do:
Rotate the shifter into gear 5.
Find the hole in the gear actuator pulley. Insert a thin tool in there; a 2 or 2.5mm hex tool works well.
Rotate the actuator pulley counterclockwise to create slack in the cable. Unseat the housing at the fulcrum lever.
The cable anchor will be easy to disengage from the pulley with the slack in the cable. Remember that the anchor has two flat spots that you line up with the opening to get it out; rotate the anchor counterclockwise about 5-10 degrees for this.
The pulley is spring loaded and will rotate clockwise and will come to rest as shown below. Remove the tool from the pulley.
Loosen both axle nuts with a 15mm wrench.
Use an allen wrench to loosen the belt tensioner from the rear of the bike. Most bikes use a 4mm allen wrench, though some are 5mm.
The belt will have enough slack now to move it off to the right side of the hub/frame so that the wheel can slide out towards the rear.
Installation is the same as removal but in reverse.
Lift the belt while you slide the wheel into the frame's dropouts. Take care to line up the brake rotor between the pads.
With the wheel all the way forward, ensure that the belt is fully seated on the front ring and then mount it onto the rear cog.
Tighten the belt tensioner to proper specs (1/2 inch deflection). Theoretically, you would turn the tensioner nut the same amount of times you loosened it earlier, but that only works if it was correct to begin with. This article covers belt tension: Tensioning a Gates Carbon belt.
Align the wheel straight and tighten both axle nuts with a 15mm wrench.
To hook up the shift cable you will loop the cable around the hub pulley, seat the cable anchor, and pull the cable housing forward so that you can seat the housing in the fulcrum lever. Remember to use the thin tool inserted into the pulley to help rotate it.
Put the thin tool back into the hole in the actuator pulley. Rotate the pulley counterclockwise and hook up the cable anchor; run the cable behind/inboard the tool you are using for leverage.
Seat the housing in the fulcrum lever.
Let the pulley rotate clockwise until it comes to rest. Remove the tool and rotate the shifter back and forth twice to make sure everything is seated correctly.
That's it - go ride!