What is the key sentence of the text?

"Rather than spend time seeking out a guaranteed technique for promoting student creativity, teachers might better spend their time focusing their attention on how their everyday classroom policies, practices, and procedures support or hinder creative expression. Indeed, creativity researchers have argued that the best way to promote student creativity is for teachers to encourage and model the creative thinking and behaviors in the classroom. For instance, teachers might encourage and model the expression of original ideas by encouraging students to imagine various perspectives on a key historical event. And they might, at the same time, help students use their evaluative skills by ensuring that imagined perspectives offered by students have some basis in historical documents, records, and other appropriate source materials."

The above from the book I study. What is the key sentence? What does the underlined sentence mean? - especially the rese words.

Thanks in advance.