Add custom module fields to search index

Hi,
We are currently looking into implementing some custom faceted search features and have a question about how to index custom fields.
I have created a new custom module and added a field called "ShortName". I have already added it to the search results widget and the search index under the advanced settings. I re-indexed the site but the values for the short name do not seem to be showing up in a search. Is there something I am missing or misunderstanding when it comes to implementing this functionality?
I have a found a lot of articles about adding indexed searches to custom fields but most seem to be pretty out of date or for older versions of Sitefinity. Any guidance or newer articles you could point me in the direction of would be great.
Thanks