1: Download the extension as zip folder from "https://github.com/osseed/com.osseed.sms.mysmsmantra".
2: Extract the folder to the extension directory in CiviCRM if already exist otherwise create the new directory and set a path in "Administer -> System Settings -> Directories", fill in "CiviCRM Extensions Directory" field and click "Save" at the bottom of the page.
3: Now install the extension with "install" link on "Administer -> System Settings -> Manage Extensions" page.
4: After installation go to "Administer -> System Settings -> SMS Providers".
5: Select the "My SMS Mantra" from select field. In the Title field give any title. In Username field give the valid username for MySMSMantra account. In Password field give the valid password for MySMSMantra account. From Api Type select http. Keep API Url as it is. In the Api Parameter enter "sender_id=sendername of MysmsMantra account". Save the form. 6. Now sms can be sent to contact.