Link to Formit with preselected option?

Hi, I’m a newbie to Modx Revo and excuse me if the question was already answered somewhere else.

-I have an event listing page that is generated with TVs from new resources (date, event name, text, ect...)
-There is a reservation page with Formit with a list of options (that is title of the events and the date).

I want to create a link in each Event listing that directs to reservation page with the option value preselected.

What do I use, and how?

The thing is that the date, event listing changes automatically day to day and so does the reservation select options. At the moment they are listed with pagetitles...

I’m totally at a loss to where I can start. Appreciate any hints or help.

thanks,jazzybuzz