No, you are not dumb at all, it is normal and very smart to ask question.
Humidity is the percentage of water in the air.
For Hermann, the humidity should not be to high (around 40-60%) but it is important to provide a ''humid hide'' if you are are using a dry substrate. I have Aspen in Hermy's enclosure, so I have a humid hide, there is a wet sponge that holds with a screw on the top inside his hide. In the humid hide, the humidity is around 80-90%.
Did you decide on what substrate you will be using for Crush?
According to me, Moisture; dampness; a moderate degree of wetness, which is perceptible to the eye or touch; used especially of the atmosphere, or of anything which has absorbed moisture from the atmosphere, as clothing
Relative humidity is defined as the ratio of the partial pressure of water vapour in a parcel of air to the saturated vapour pressure of water vapour at a prescribed temperature. Humidity may also be expressed as absolute humidity and specific humidity. Relative humidity is an important metric used in forecasting weather. Humidity indicates the likelihood of precipitation, dew, or fog.