Job manager extend search

hi, i bought a theme and i am using job manager plugin.
i would like to extend the result of the search job option.
i want to allow my users be able to use some terms in there search keywords.
i mean boolean search, and relevant search with more than 1 keywords.
please help.
i tried to add relevansy plug in but it’s not working.
Thank you

https://www.ads-software.com/plugins/wp-job-manager/