Where do you put apostrophes in this expression: Dos and donts

Apostrophes are used for possessive forms (none here), contractions (one here), and a few types of plural forms.

http://grammar.ccc.commnet.edu/grammar/marks/apostrophe.htm
Scroll almost all the way to the bottom to read about the special plural forms. Read and study about those and about contractions, and then let us know what you think.