You can park your car for free in the parking garage 'Parkeergarage Houthavens'; it is directly under the studio. The easiest way is to navigate to the parking garage and not to the address of the studio. Take a ticket to enter the underground parking garage and park your car in the dark blue/dark purple zone (not purple/pink).
You reach this zone by driving to the end in the garage, turn left and turn left again at the wall. At the end of this path you will find the right zone, with the elevator that will take you directly to Ancora's Health Studio on the second floor. The zone and elevator are on the same level as where you entered the parking garage.
Give your parking ticket to the host so it can be scanned and you can leave the parking garage for free at the end of your appointment.