HI Raniya,

To select a time according to our preference in BITSAT follows these steps:-

1. Go to the BITS admission portal @ bitsadmission.com (//bitsadmission.com) .
2. Click on the BITSAT slot booking link.
3. New window of “Online Test Booking System” (OTBS) will open.
4. Login using application number and password.
5. Students will see the test city allotted to them in OTBS.
6. Select the test date from the list.
7. Select test venue and timing of exam.
8. Verify all the information.
9. Click on the confirm button to book the slot.
10. Students will receive the confirmation message for successful slot booking.
11. Students will be issued admit card for appearing in exam after slot booking.

No, there is no common time for BITSAT like NEET.

Refer here for more info - https://engineering.careers360.com/articles/bitsat-slot-booking

Feel free to ask doubts in the Comment Section.

I hope this information helps you.

Good Luck!