How to edit CSS for Ultimate Member directory filters

Hello, I am currently using Ultimate Member for managing two user types. I have set up two separate user profile forms, each containing ~15 custom questions/fields. I have added the custom fields to each member directory, but on the front end of the site, the dropdown filters are displayed horizontally, and I would like for them to be displayed vertically- like a sidebar.

Because each member directory has so many filters, they span across the screen to the point where they are cut off on the right side of the page and are no longer visible. I think this is a CSS issue?? How do I adjust the filters so that they are displayed vertically on the side of the page (like most websites)?

NOTE: I am very new to websites and still learning (a lot!), so breaking it down would be GREATLY appreciated.