The 'Replace' function in 'AutoCorrect' doesn't replace anything

How can I activate the ‘Replace’ function in ‘AutoCorrect’? I have put in a few replacements, but, when I type, neither those nor any original ones happen.

The language set in your document must match the language set in AutoCorrect Options for Replace. If you have document language set to None then AutoCorrect will not do anything.
Make sure that Tools > AutoCorrect > While typing is ticked.

That’s what it was - While Typing needed to be checked. Thank you!
I would put ‘solved’ in the subject line but I can’t find a way to edit it.