Help with Organizing Catalogs in Lightroom Classic

Hello

I am helping a friend with Lightroom Classic on an Imac (Monterey 12.2.1), managing to transfer 7500 RAW files to a “Library Catalog” on an 2TB external hard drive and freeing up a lot of his internal disk space.  

However I am essentially “flying by the seat of my pants” here.  I’m wondering if there are some good training resources that cover the finer points of Lightroom Classic organization - creating multiple catalogues, importing and exporting between catalogues, hard drive setups, etc.  Not only just how to do it, but what is the optimal setup for one’s particular workflow.  I’m more of a reader than a video person so that would be my preference.

Thanks in advance for your help.