Here is some ideas:
1. Show a popup beside the launcher at the first start after the installation that encourages the user to click it.
2. Use an attractive color combination of the button for make it stand out from the other buttons.
3. Show a slide to inform the user that the ubuntu-button is clickable can be another solution.
Here is some ideas:
1. Show a popup beside the launcher at the first start after the installation that encourages the user to click it.
2. Use an attractive color combination of the button for make it stand out from the other buttons.
3. Show a slide to inform the user that the ubuntu-button is clickable can be another solution.