Rules for Daily Work Schedule Variants

Hi,

I am new to Time Management, can you please make me understand how to configure "Holiday Class" and "Holiday Class Next Day" in Daily Work Schedule Variants.

Eg:

I am not able to understand the meaning of X in "Holiday Class" and "Holiday Class Next Day" in tha above example.

Please help me to understand the above example and its effect, i.e where it is affected.