In this video, the teacher explains how writers use appositives to clarify meaning and add interest in their writing. The teacher provides examples and guides students through practice exercises to identify and rewrite sentences with appositives. The video also emphasizes the importance of placing appositives next to the nouns they modify and using commas to set them off from the rest of the sentence. By the end of the lesson, students are encouraged to apply what they've learned and revise their own writing by adding appositives to provide more information about nouns or pronouns.