Reef Riders is located inside the Asipona marina. There are bathrooms, rinse showers, and even a restaurant (closed on Sunday) located here if you want to grab a bite to eat if you are doing morning and afternoon dive trips. If you are arriving by private car there is a lot of parking available, and plenty of taxis for as well for your return trip if needed.
When you arrive the security gate will ask your for your name and the name of the boat you are going to: Sea Car.
Google Map link

If you are driving a car there is plenty of parking.