Where can i find how "filament tracking" works

What is “filament tracking” and what does it do?

Is it possible to track how much is left on wich Colour/spool?

Yes, when you use filament tracking, the system will deduct the amount from the .gcode and calculate how much material is left.
You can set the Color from the that menu as well.

A database would be cool with a field where I can write a “code” for each spool and a field where the remaining length is stored. When changing to a different color you would then only have to enter the code of the spool and the remaining length would be reloaded. Now I have to write it on a paper, how much is left on the spool, if I change the color.

How does Filament tracking work on the Ultimaker3 or other dual extruder printers. I see only one value. When it subtracts from a file, is that strictly nozzle 1 or the sum or nozzle 1 and 2?

We are working on fixing that.

So when I put in a new filament spool I need to go in and enter the starting amount? Also, the filament spools that came with my printer show only Meters or Feet on the inside of the spool. Is there a way to change the Grams to one of these measurements instead?