Booking calendar setup

So, i have two rooms that people can book to sandstream their funriture. A room costs 20eu per 15min. Unfortunatly I don’t see how I can configure this wel.
I would like to configure it that a day can be chosen and the person fills out form an says how many time he needs. per 15 mins and then he show price times 20eu. Is I now say on a day 2 dan he shows 40 eu but the two can’t be defined.. Can anyone help me with a correct configuration or did I oought the wrong plugin. Is there a way to select times….

The page I need help with: [log in to see the link]