I agree with a lot of above points. Especially as a new investor you really dont want to take big losses right out the gate as may impact your overall view.
I would say generally maybe have a look at and research:
20-30% ETFs (some of this can be clean energy etf if you wish, but also S&P tracker like VUSA and maybe a Chinese one like FCSS or BGCT)
Then various amounts in:
Tech - Focus on some companies you like but mostly are solid like Microsoft, Amazon, Apple
Consumer - Again have some solid (Unilever, Coca Cola) and some growth (Starbucks)
Financial - Including Payments (Paypal, Visa, Amex, Stone, Square) and banks (lots here depending on country/style you want)
Healthcare - JnJ (stable growth and dividend growth), Merck, GSK (for a stable dividend)
Energy - Check out NEE which is renewables but stable and a solid dividend too. Mix with current ones maybe like Shell or BP (small amount)
Dont know much about REITS or semiconductors but I own NVIDIA in my tech pie.