Two approaches imo. You either do it as a hobby, read the papers/internet, buy and sell, make a few quid here lose a few quid there. Or you treat it like long term savings. Buy a tracker or fund, stick some money in it, keep topping it up. In 20 years cash it in. The second approach is much easier and likely to make you more money so I’d recommend that.
If you do go for that then research a few options. Fundsmith and Vanguard are popular on here and considered pretty “safe” bets. Both can be bought direct or through a 3rd party.
Final thing is the wrapper. You can just buy them, buy them as an ISA or buy as a pension. Pros and cons of all them but a mix of the ISA and pension works for me.
It’s worth doing imo. These are slightly funny times but long term you should do ok.