1.  Create your account from https://dashboard.nexmo.com/sign-up if not already created

2.  Login to your nexmo account from https://dashboard.nexmo.com/sign-in

3. Go to Getting Started and get API key and API secret

4.  To get your From Number go to Numbers -> Buy Numbers

5. You will have to fill API key, API secret and From number in the SMS Settings and click Save button