First you need to select the bike you want to see details of. When selected, the stock (factory default) gearing and tire data) is loaded into
the setup called 'Stock' which is marked with a red background.
When loading that data, almost the same data is loaded into the other 2 availabe setup's, Current (Orange) and Custom (Green).
The only difference in loaded data is the Final Drive ratio for Current and Custom. We assume that currently on your bike you have already changed your front sprocket to a sprocket with 1 tooth less
as the Stock front sprocket. This would result is slightly lower top speed and higher revs but also some more torque.
As a suggested Custom setup, we preload Custom Final Drive with the Stock Front sprocket but with a changed rear sprocket, having
3 teeth more than the Stock rear sprocket. This is a change has a similar result as what was loaded into Current setup, slightly lower top speed and higher revs but also some more torque.
See example of preloaded Final Drives here.
Of course we do not know what you have done to your Current setup nor do we know what you intend to do to your bike in Custom setup so you are supposed to change those fields (and any others)
to reflect your Current and considered Custom setup.
In order to not having to change those fields every time you load your bike, after you have updated all fields you can Save your Personal Setup and load that instead the next time.