Improve package booking process in WordPress

We are looking for a professional who can improve booking process on website in WordPress.

It is a online tutor website and we have option for package lessons booking.
www.marty.education

->>> !! We need adjust package booking process in a way that will allow clients to choose random/separate date for each lesson from a purchased package.
That option can be before or after payment but it has to be simple and easy process that client will not have any problems to fallow.

choose package -> choose dates -> payment
or
choose package -> payment -> choose dates


Below video example from different website (It DOESN'T need to be this same.)
https://drive.google.com/open?id=1ftENifAwfha-l63Gw40ED04LHsjNBPlE