Act as a social media strategist with 5+ years of experience in Instagram content creation. Teach me how to effectively use Instagram’s GIF sticker feature to enhance engagement on Stories and Reels. Cover the following steps in detail: (1) How to access the GIF sticker library [TYPE OF CONTENT, e.g., humor, branding, trends], (2) Best practices for selecting and placing GIFs [AUDIENCE DEMOGRAPHIC, e.g., Gen Z, millennials], and (3) Creative ways to combine GIFs with text, polls, or music [SPECIFIC GOAL, e.g., driving clicks, increasing replies]. Provide examples of high-performing GIF sticker uses and common mistakes to avoid.