I’ve been vegan (with only very minor lapses when BF) 22 years. The vegan society UK has lots of good info on their website.
I know some say you don’t have to supplement, but it is recommended and I know I feel better for it. There are some nutrients- iodine, B12 etc that are difficult to get consistently otherwise. Before anyone starts seaweed is not a reliable source of iodine as it varies too much. The vegan society sells a very good value for money supplement for vegans veg1. I take this every day, in addition sometimes I take magnesium/calcium supplement etc (I do a lot of strenuous sport) and an algae based omega 3 supplement, and spa tone iron. I’d recommend the veg1 as essential really. I’ve found my sporting performance has increased dramatically since supplementing!
Some of the nutrients available in dairy/meat is only there because the animal or animal feed is supplemented. Eg iodine in dairy is there because the cows teats are cleaned with iodine! We get told to eat fish for omega 3, but they get it from algae, so by just taking the supplement made from algae, it’s possible to avoid eating fish, but still get the benefit. Animal feed is enriched with nutrients, but you also get less welcome additions such as traces of antibiotics etc in your food.
You can survive as a vegan without supplementation but to feel at your best then supplementing is sensible, and there’s nothing wrong with that, andmeat/dairy production is so unnatural (artificial insemination of cows etc) that it’s not such a big deal.
Vegan cookbooks used to always give loads of dietary info but they don’t really do that anymore. However, if you’re going vegan it’s worthwhile basing your diet on whole foods and avoiding things that have no nutritional value (vegan cheese I’m looking at you). There’s a lot of stuff on the internet and quite a lot of it is crap. I complained a BOSH recipe didn’t work at all, and they didn’t even get back to me/do anything. I think a lot of internet stuff is about how things look, rather than taste, and books are generally more reliable, although the Minimalist Baker is a good, reliable site, and her vegan Parmesan recipe is both nutritious and tasty. I’d also recommend Katy Berkow’s 15 minute vegan, it’s my current favourite book!
There is, unfortunately, a lot of bad info/science out there about Veganism. I liked Cowspiracy but What the Health was, frankly, a load of BOLLOCKS. Veganism doesn’t cure people of ailments, although it does reduce your risk of certain diseases eg many cancers, heart disease etc. I’m on shitloads of medication, despite What the Health suggesting a couple of weeks as a vegan and I’d be able to ditch it all 