What is an equivalent expression to "How to" that is used when searching/referring to guides, especially online?
There is no equivalent. One way would be to change the verb where appropriate and make something like 寿司の作り方、漫画の描き方、ボスの倒し方, etc.
Or as the other answer said, use a generic word like 方法.
When English nintendo website use “How to Charge the Controller”, In Japanese nintendo website use “コントローラーを充電する”. It has no meaning of “how to”, but this is a popular way. You can use “コントローラーの充電のしかた” too.
When you google “How to become a teacher?“ in Japanese, you should use “先生 なる 方法” or “先生になるには”.