What to do? Where to start with investing in stock and ISA?

Getting a bit confused with all the possibilities of investing, all the platforms too.

Where should I start 30(m)? It seems to be too late, or I missed a chance to invest.

I’ve been thinking to put some money in ISA stocks and shares or opening an account with Trading 212 and monthly investing in the Vanguard FTSE All-World fund, but then what would be the best investment??

Which one? Something to help to grow money and wealth, possibly help to retire early, probably not realistic with stocks, but what's your opinion?

Any advice? What are your monthly investments ?? How are you managing it month to month?