Follow these steps, please.
1) Use a DIN-BTA adapter to connect your Colorimeter to Channel 1 of your LabQuest.
2) Place a blank cuvette (about 3/4 full with distilled water, or the solvent of choice) in the Colorimeter and turn the control knob to 0%T.

NOTE: Allow the Colorimeter to warm up for 5 minutes.

3) Turn on LabQuest.
4) On the Meter screen, tap Sensors and then tap Sensor Setup…
5) Tap the space next to CH 1 (it will say “No Sensor”). A list of sensors will appear.
6) Scroll down until you see the Colorimeter, and then tap on it to select it. Tap OK. “Colorimeter” will now appear in the space next to CH 1.
7) Tap OK to go back to the meter screen.
8) Tap Sensors and choose Calibrate: CH1: Colorimeter.
9) Tap Calibrate Now.
10) In the box next to “Value 1”, type 0 (for 0%T). Tap Keep.
11) On the Colorimeter, turn the control knob to the desired wavelength.
12) Again on the LabQuest, wait for the live voltage reading stabilizes (it takes a few seconds), type 100 (for 100%T), then tap Keep.
13) After the screen changes, tap OK. The LabQuest will go back to the meter screen again. The Colorimeter is ready to use.

There is no way to store this calibration, thus it needs to be done each time you use a Colorimeter.
Also, the calibration is only valid for the wavelength you selected. If you change the wavelength, you need to calibrate the Colorimeter again.

Related TILs:
What model Colorimeter do I have?
How do I calibrate my older Colorimeter?