The training zone calculator does automatic calculations for various heart rate training zones based upon several well known systems.
The first few columns (Borg, Borg descriptor, Thinking speaking scale, % of heart rate reserve and heart rate ) are based on The ACSM guidelines and Sports Physiology books. The last 2 are based on the training systems by Carmichael and USATF coaching guidelines.
You can use the calculator without having performed the Carmicheal or USATF tests but you must enter your age. This will estimate your max and resting heart rate ( or use the ones you entered ) and calculate HR values for the two lactate thresholds and corresponding borg zones.
If you've done either or both the USATF and Carmicheal test then these will be calculated as well.
For LT1 the Carmicheal heart rate seems way off and I haven't found any reason for it but if you're riding for hours then it obviously can't be so difficult that you can't ride for hours.

The % of HRR or Heart Rate reserve is not a calculated number but the expected percentages that the Borg scale corresponds with Heart Rate reserve.  Heart Rate Reserve is the difference between max heart rate and resting heart rate.  The Heart Rate column is the calculated heart rate based on your age and HR Max and resting HR.

LT2 is a little hazy because Lactate Threshold training is done just below LT2 and not right at the threshhold but while the threshhold itself will be at a specific place for each person everything is given in ranges.  LT2 is in Borg scale 16 at 79 to 84 percent of your heart rate reserve the training systems have it in the lower zone but the reality is that Lactate threshold training is probably between the two.

References:
ACSM's Guidelines for Exercise Testing and Prescription
Sport Physiology for Coaches
The Ultimate Ride
USA Track and Field Coaching Level 1 Curriculum textbook ( as far as I know it's only available if you take the course )