To respond to a request, you can:
You can also look through your bookings by their status (new, pending, etc..).
Before accepting a booking request, make sure to have looked over the pick-up and drop-off times, your remuneration, their travel plans, and the dates. If everything seems to suit you, then you are free to accept.
N.B. You can of course talk to the renter beforehand via the messager service if you want to find out more about their travel plans!