Archie Trammell has a radar course that has been the gold standard for years, A Google search, and/or search of this forum will turn up lots of links to radar courses. Here's the web link to Trammell's current material,
Home - Radar Training Systems (radar4pilots.com). There used to be videos, with Archie narrating (he was a radar expert, not a trained actor/narrator, he passed away a few years back), but it looks like now the material is digital text and quick-reference manual. There are other radar courses/learning materials available as well, but I'd bet 9 out of 10 experienced posters on this forum will mention Archie Trammell. (Just a suggestion, I'm not trying to be a smarta$$, there's just too many factors, height of storm, temperatures, precipitation gradients, cell-shapes, etc,, to list a few simple rules of thumb.)