Filter gravity form entries?

This is exactly what i am looking for , but not sure how to make it work .
So i’m using gravity forms for a directory-like site, to allow a user to submit posts , which will act as listings . Well those posts have custom fields , like checkboxes/dropdowns . The thing is that i dont know how to filter them with your plugin , as those fields don’t appear in taxonomy or meta field setting.

example :
A choice field (+ high , +medium , +low ) and users is able to select just one . Now , on my posts page i want to live filter just the posts with +high .

Thanks , Eddy

https://www.ads-software.com/plugins/ultimate-wp-query-search-filter/