To use the 'Add Yours' sticker on Instagram Stories, follow these steps:

  1. Open the Instagram app and start creating a new Story by swiping right or tapping the plus icon at the bottom of the screen.
  2. Select a photo or video to edit, or capture a new one with the in-app camera.
  3. Tap the sticker icon at the top of the screen and choose the 'Add Yours' sticker.
  4. Write a prompt or challenge for others to respond to by adding their own stories. You can suggest a theme or any topic relevant to your story.
  5. Customize the sticker by adding text or resizing it if needed.
  6. Tap 'Done' in the top right corner.
  7. Add stickers, texts, or effects to your Story as desired.
  8. Once finished, share your Story by tapping 'Your Story' or the arrow pointing down at the bottom of the screen.

To join someone else's 'Add Yours' Story:

  1. Find a Story with an 'Add Yours' sticker.
  2. Tap on the sticker.
  3. Tap the blue 'Add Yours' button at the bottom of the screen.
  4. Create a story with the background or media of your choice, and customize it further with text, stickers, or effects. You can move or resize the 'Add Yours' sticker if needed.
  5. Tap 'Your Story' or the arrow pointing down to publish your Story, which will now join the chain started by the original 'Add Yours' sticker.

Remember that 'Add Yours' stickers can promote engagement, community, and creativity, so consider using them to start a theme-based Story chain or join one to connect with like-minded users.