Hi, you don’t need to do anything special in terms of a search form or box for Better Search to work as it can work with any default one that you have with the theme. There is also a Better Search form widget that you can add to widgetised areas.
e.g. you’ll see it on my site https://webberzone.com/ The search icon to the top right opens up the default box of my theme Kadence and the results are those of Better Search.
My docs need quite a bit of work and it’s what I plan to do alongside the premium version this year.