What do you mean I need a life? =P Hm... Lives... Isn't that something that you get in Super Mario Bros? You know, those green mushrooms? That's a life, right?
It just gives you a guideline to use when creating your own sprites in the style of LttP (and other games). Each game only used a certain number of colors for various aspects of the game (sprites in particular) so using the same colors that were used in the original game tends to improve the overall feel of the sprite.