Press f12, click console. Write: SugarCube.State.active.variables.
And then just add the name of the var you are trying to change after that and put an = and your value. So let's say i'm trying to change a var in game for lust to 50. It would go like this:
SugarCube.State.active.variables.lust = 50
To be noted certain stats are encapsulated in objects. So let's say there's a character called lea. It would go like this:
SugarCube.State.active.variables.lea.lust = 50