Simple search returns zero results

New to Grav, coming over from Wordpress.
I have the Antimatter theme and the simplesearch 1.14.1 plugin
I’m getting a search box in the side bar on my blog page (good) but when I search it always returns nothing.
I messed about with the simplesearch.yaml file, changed it from
category: blog
category: page
Still nothing.
I saw some old posts here with similar problems and they said update to the latest version, but I just installed this so I assume I already have that.
Any ideas?

Okay, I figured it out. The docs said to ‘keep the filter section empty’ so I deleted it and got zero results. But eventually I tried just leaving ‘filters:’ in there with nothing under it. Took ages to come back with the first result so I guess it was building an index. Second result was fast, both were correct. So my working simplesearch.yaml now looks like this:

enabled: true
built_in_css: true
built_in_js: true
display_button: true
min_query_length: 3
route: /search
search_content: rendered
template: simplesearch_results
filter_combinator: and
ignore_accented_characters: false
by: date
dir: desc