I would suggest using the ETF category to get suggestions and help for ETFs as a good starting point.
To figure out all the types of sectors and industry, you can use Yahoo finance screener, then use the dropdown under "sectors" and it shows you list. After selecting a sector you can choose an industry - which is another list.
You can also goto finviz.com and select "maps" you'll see all the type of sectors visually, you can also use the screener.
Glad you started early. Good luck to you.