If you are using an English keyboard, you may be in for a few surprises. First, the positions of the Z and the Y key are reversed, since Y is used more often in the English language than Z. Also, there are no separate keys for háčky a čárky. Instead, they are located under the Symbols (zvláštní znaky) and must be selected and inserted.
2011, Charles Ota Heller, Prague: My Long Journey Home, “A note about Czech words”, page v
“Čárky” (pronounced “tchah-rky”) are used to lengthen the sounds of vowels. “Háčky” (pronounced “hah-chky”) are used to soften the sound of consonants. For example, “s” is pronounced the same as in English, but “š” becomes “sh.” By far the most difficult Czech letter for English speakers is “ř,” to which the closest approximation is a rolled “r,” followed by “zh.” Thus, the famous Czech composer, Antonín Dvořák, is pronounced “Antonh-een Dvor-zh-ahk.”