Andy Astbury's Youtube channel is probably the best up to date source of videos. His videos are image oriented. He uses also Photoshop, so he knows also the other side.ART is a very nice development that is forked from Rawtherapee and very actively developed. Try a nightly version for the very latest.
For RawTherapee and ART you can unfold the 7z (ZIP) in Windows and simply start the EXE file without installing them. I always have several dev version on my drive.
If you get confused by the different version:
W64_generic - whenever you are unsure
W64_haswell - Intel 4th generation CPU (2013)
W64_Skylake - Intel 6th generation CPU (2015)
W64_Icelake - Intel 10th generation CPU (2019)
W64_znver2 - AMD Zen (I am guessing)