How to find world market index symbols in different brokers (i.e. TOS, RH)

I use Thinkorswim to check on the E-Mini S&P 500 futures, ‘ES20’, but I also want to see the FTSE 100, CAC 40, AEX, Hang Seng, etc. But when I enter those names to the search field I get no results, or multiple mixed results. How can I find the world indices equivalent to the S&P 500 futures and be sure I am looking at the right symbol?