Changing Default Availability not working

I have a website wich has a crossfit class booking system. The calendar made with pinpoint booking system, just shows on the website one week available at the time, and every sunday at 7pm it makes the next week available with classes from 7:30 am to 9pm wich have a default availability of 14 people.
Due to covid and social distancing i need to decrease the availability from 14 to 9 people. According to pinpoint documentation i need to click on the calendar in the admin panel and it should display the calendar and a left colum with the options to change availability settings. The problem is that when click on the calendar item, it does show the calendar in the center column of the page, but it does not show the left column with the availability settings. The plugin only let’s me change change manually the availability by clicking whole week, in that case it displays the left column and i can edit classes availability. Does anyone have any clue on where to find the default settings? The website was not made by me, and i can’t reach the person who made it.