Use a straight single quote (') and not a smart quote (’) or back quote (`). Do not use two apostrophes in place of a quotation mark. To avoid the use of smart quotes in Google Docs, go to Tools > Preferences and uncheck the "Use smart quotes" checkbox.
To show possession for words ending in s (plural or otherwise), add the apostrophe to the end of the word.
- Correct: Jesus', the class' noise, the classes' books
- Incorrect: Jesus's, the class's noise, the classes's books