- Click inside a record in your custom module
- Top right ... (3 dots) navigation, click it.
- The last option on that list is Create Button. Click it
- What would you like to name the button? RingCentral SMS
- Where would you like to place the button? View Page
- What action would you like the button to perform? Open a Widget

7. Create New Widget
8. Name: RingCentral SMS Widget
9. Widget Type: Button
10. Hosting: External
11. Enter this link:
If the extension was sent to you a long time ago, use this: Private (V74.0): https://9d1f1cb4-23af-4093-a7b9-43b67714701e.zappsusercontent.com/appfiles/v2/9d1f1cb4-23af-4093-a7b9-43b67714701e/58.0/ddca91d3f2eeb39b2534a019495164764b74a8859565a90bd75c4a98998fb67d/app/index.html
Video instructions: