How to use Group meetings with different dates/times

I can’t get my Group meeting to allow me to select the specific dates and each date has different times for a group of onboard classes I need to offer a client. They aren’t every date at 2pm. Some are at 10AM, some are at 9AM on different days. They are not even every day. 

And for some dumb reason, it won’t allow me to select the first date of this series claiming there are not time spots available on my calendar BUT THERE ARE. Why would it be confused?

Am I trying to get the tool to do something it is not built for?