128. Capitalization in Titles

Capitalize the first letter of the first and last words in a title and of all interior words except the following: articles (a, an, the), coordinating conjunctions (and, but, or, for, so, yet), and prepositions (including the to of infinitives). Capitalize all words except articles, coordinating conjunctions, and prepositions--unless one of these is the first or last word.

(CMOS)

Or use this site:
https://capitalizemytitle.com/style/Chicago/