I want to ask if there is a possibility for me to block the hours I can not work? For example... I am free every day, but I am not free for 3 hours, 4 PM to 7 PM. Is there a way I can do that on my calendar with time slot?

Unfortunately this seems to be a flaw with the Rover scheduling system and should be changed. As of now, you can only set your availability per weekdays or weekends, not per specific day. For many of us, this job works around another one, and as not everyone works a steady 9-5 type of job, the calendar should reflect that. For example, I have full-day availability on Wednesday’s, but only half-day availability every other weekday. I should be able to set my calendar to align with my specific day-to-day schedule.

You can go to edit your profile, services and rates, service options, and select or unselect preset availability. I also put my specific availability in my about me part of my profile