I found this a very easy to understand (with a nice image) the predicates:
https://docs.qgis.org/3.28/en/docs/user_manual/processing_algs/algs_include.html#id5
(in documentation, you may need to scroll a little bit down to see the paragraph on the predicates)https://docs.qgis.org/3.28/en/docs/user_manual/processing_algs/algs_include.html#geometric-predicates
