Hello Aspirant,

Slot booking is nothing but similar to registration or reserving a seat for yourself , or it could be registering yourself for an exam which is conducted multiple times in different centres ,
Slot booking could be date, time or test centre,which will be available for limited period of time,

Slot booking facility gives you freedom to write exam on your selected dates and times, slot booking is important and mandatory for writing exam.

I hope the above information is useful to you ,

All the best !