You just need one global stock with
over 3000 companies in. That's it...
I use trading 212.
Stocks and shares ISA.
Open account.
Use a promotion code where you get a minimum of £20 random stock free. I got Lloyds UK...
Buy a global ETF. I recommend Invesco FTSE All World UCITS ETF Acc. Must be the ACC (dividend reinvest) not the DIV
(Dividend payed to you)
Put in what you can afford every month for next 10+ years. Anything from £1 to £1000
Now investing.
I have a small punt on individual stocks but you must be an active investor. This is more complicated and risky but you need to understand what you are doing.
I can post a video walking you through step by step that got me going.
Wish I done it years ago