25 year memory loss

[Dijon]

Courtesy of grandkids, coming back to this hobby after 25 years and find that I've pretty much forgotten what little I knew back then. Are there any books ( or websites) that can be used as a complete idiot's guide to catch up on what I've missed and where we are now?
I've still got my old Super Dogfighter and Losi XXX and intend to stick with them as platforms, but what should I be running them on in terms of motors, batteries, esc etc?
Any advice appreciated.