How do I put my tone marks in pinyin?

How do I put my tone marks in pinyin?

Always insert tone marks above the vowels. If there is more than one vowel letter, follow the steps below:
(1) Insert it above the 'a' if that letter is present. For example, it is rǎo and not raǒ
(2) If not, insert it above 'o'. For example, guó and not gúo
(3) Insert it above the letter 'e' if the letters 'a' and 'o' are not present. For example, jué and not júe
(4) If only 'i', 'u' and 'ü' are the only present letters, insert it in the letter that occurs last. For example, jiù and not jìu, chuí and not chúi. Note, if the vowel present is ü, the tone mark is put in addition to the umlaut. For example, lǜ