Max Speed For 5 Minutes 
The maximum speed that you can sustain for 5 minutes on a flat and smooth road surface with minimal headwind. 
Average Speed For A 60 Minute Ride 
The average speed that you sustain for a 60 minute ride on a fairly flat and windless ride.
The first two questions are used by the calculator to estimate fitness, if you don't know the answers then you can guess but an accurate answer is better.

Bike Type 
The rolling resistance of tyres has a noticeable effect on the amount of power needed to ride at any particular speed.
Road Bike Racer is intended for bikes with 2328mm tyres and Tourer for wider tyres. If you are riding a bike type not specified here Hybrid will be a decent match. 
Riding Position 
Modern road bikes come in between 7kg and 12kg with older non alloy steel bikes a couple of kg more, very cheap bikes can weigh as much as 20kg. 
Bike & Luggage Weight (kg) 
Modern road bikes come in between 7kg and 12kg with older non alloy steel bikes a couple of kg more, very cheap bikes can weigh as much as 20kg. 
Start Ride 
The day number and time in the simulation that the ride starts at, hours should be in 24 hour clock format, 1pm = 13. 
Riding Time (Minutes) 
How long the ride lasted for. 
Average Ride Speed (mph) 
If you have no idea then somewhere between 12mph which is long distance touring speed and 16mph which is reasonably cycling fit 
Watts 
If you know what your average power for the ride was then you can enter it here and this value will be used instead of a calculated one. For clarity,
riding at 20mph is around 200 watts on a road bike. 
Adjust Recovery VO2 
In order to calculate the energy cost of the exercise, the calculator tries to estimate the percentage of VO_{2}Max that this ride represents.
This option allows you to specifiy an ajustment to this calculation.
The main reason for allowing this adjustment is that the calculation has a
large margin of error as it is such a personal calculation. 