Ahhh the warhams!!
I don't play since I had the kids but I still do paint now and then. I mostly do scenery making these days for my brother's 40K group but I still get the odd mini done just to please myself.
I would honestly say - watch as much youtube as you can. I started back in the old days when there wasn't even painting advice in White Dwarf, and everything I learned I learned from screwing up, painfully
The big youtube painting channels have absolutely SUPERB tutorials now for every level of experience, and a lot of them have beginner level content which is absolutely excellent.
I would also say that the reviews of painting products, and the different types of products available, have been absolute gamechangers in the last decade. There is a beginner friendly painting method affectionately called 'slapchop' that uses base paints and washes (including the Citadel ones) to produce really great results for beginners and produces them quickly if you are interested in putting together a battleforce or even a whole army. Miniatures tend to inexplicably multiply in homes for some reason...
Channels I would suggest you check out:
Juan Hidalgo
Squidmar (more for the entertainment than the tutorials strictly, but a lot of the painting channels are great fun. These lads are hilarious)
EonsOfBattle
Ninjon
whiff already mentioned MidwinterMinis
Stahly (Tale of Painters) especially for paint and tool reviews
Zumikito Miniatures
Vince Venturella
Duncan Rhodes Painting Academy just to marvel at his skills!!
I watch hours and hours of painting and scenery content every week, sorry for the Labrador-like enthusiasm....