1. Go to Glide.
2. Create a form with fields for name and signature.
3. Add a button for form submission.
4. Create a new action and name it "conditional."
5. Add a condition: if the signature is not empty.
6. Set action to show a success notification if the condition is met.
7. Set action to show a failure notification if the condition is not met.
8. Change the failure message to "Sign first, please."
9. Test the form by leaving the signature empty and clicking submit.
10. Verify that the failure notification appears.
11. Add a signature and click submit again.
12. Verify that the success notification appears.