As for YouTube channels and podcasts, these are among my favorites:

Retrogaming on Youtube

Gaming Historian Pat the NES Punk Game Sack

Special Interest

Retrozirkel (German audio podcast about a single classic game in each ~1h episode) Matthew Colville (Paper & Pen and D&D, I highly recommend his "Running the Game" series to any P&P gamemaster.) Shadiversity (medieval weapons & armor in history, reenactment, and gaming)

You can start with the docs - https://retropie.org.uk/docs/First-Installation/.