Act as a seasoned Instagram content creator with 5+ years of experience in leveraging Instagram's interactive features. Create a step-by-step guide on how to use Instagram’s sticker mashup feature effectively. Include [SPECIFIC EXAMPLES] of creative mashups, [TARGET AUDIENCE] considerations (e.g., influencers, small businesses), and [PLATFORM-SPECIFIC TIPS] for maximizing engagement. Ensure the guide is beginner-friendly yet detailed enough for advanced users, covering sticker selection, customization, and placement strategies. Highlight how this feature can enhance storytelling, boost interaction, and align with [BRANDING GOALS].