rotate an object in a specific direction of space

hi,
I have a gauge object whose cursor I have to rotate through a slider in a specific area in space, how can I use the quaternions to set the right rotational values?

hello you can use this method :

//0 : minimum of slider
//1 : maximum of slider
 float SliderValue= Mathf.InverseLerp(0, 1, var1);
//0 minimum wanted rotation of your gauge
//360 minimum wanted rotation of your gauge
 float CalculatedRotationbasedOnSLiderValue= Mathf.Lerp(0, 360, SliderValue);