G00/01/02/03 are motion commands

G0 is the G-code to command a rapid motion at the previously set speed to, typically, XYZ, e.g. G00 F50 X0 Y0 Z100. which will move rapidly to 0,0,100 at 50mm/min. In your setup the speed is defaulted to 5000mm/min

G1 would typically be used to command a cutting motion e.g. G1 F10 X100 which would move at 10mm/min to location X100 (Y and Z being what was previously set). In your setting F = 4000mm/min, however the NC setup of 76mm/sec is 4560mm/min which is too fast and likely to stall the motors, but its overridden by NCStudio. The operational number must be less than the fastest motor setting

G2/G3 are clockwise and anticlockwise circular motions

The distance moved should be independent of the speed moved at. Changing the speed should NOT alter the distance moved, just how fast it gets there...

If its cutting too deep/moving too far it probably means that the steps/mm setting for the relevant axis is wrong rather than the G-code. There must be another setting somewhere...