Sms api integration

can some one help me send sms via api from a form. i am stuck. screen shots will be very helpfull

this is example code they provided for using api.

POST /v1/messages HTTP/1.1
Host: api.messagemedia.com
Accept: application/json
Content-Type: application/json
Date: Sat, 30 Jul 2016 05:18:52 GMT
Authorization: hmac username="uCXUdoogNfCsehEClbO2", algorithm="hmac-sha1", headers="Date Content-MD5 request-line", signature="Ia4G5lkhH/3NDYpix+8ZHUnp6bA="
Content-MD5: 5407644fa83bec240dede971307e0cad
Content-Length: 133
{
  "messages": [
    {
      "content": "Hello World",
      "destination_number": "+61491570156",
      "format": "SMS"
    }
  ]
}