I know how to use the concordance to find all the words of Christ but how do I do that for other speakers in the Bible. For example, how do I search to find all the words that Paul used?
Welcome Ricky,
Not sure what 'concordance' you mean.
You can use {Speaker <Person Paul>} in a Bible Search. For other people type e.g. <Person John and click the suggestion that matches what you want.
Or you can use Tools > Bible Browser as below:
