Not all funds labeled "index" are actually a good choice. Some "index" funds charge a gigantic 1.5% or more in management fees. So it is not done just learning that "index" - funds are good, you still have to look out and study closely all the cost of each fund you are contemplating adding to your portfolio.
Below some examples of "index" - funds, and the costs occurred by the investor:
note*: the above list was edited to our best knowledge and on the dates indicated. The list is not final, as the funds and the available information shift often and unannounced.