Hello, I've recently started growing veg. i think the trick is to start small and build up. this year i'm growing courgettes, tomatoes, aubergine, raddichio...i lost a few items too! I grow quite a lot of herbs too.
i bought all my seeds from B&Q, but you can go to any garden centre, or order from suttons online. you'll need sowing compost, some seed trays, a greenhouse (mine is plastic - can't fit a full size glass one in my garden), a propogator maybe...it depends on what you want to grow and how much space you have. my spare bedroom was full of seedlings for about 2 months while i was geminating my seeds but it was worth it, and it's so rewarding watching them grow!
i found watching gardeners world really helpful (Monty Don grows loads of veg) and talking to people - you'd be surprised how many people do it these days.
to be fair though, the best way to learn is to try. and learn from your victories and mistakes. hope this helps?