360 SMS App helps the user to send SMS from custom Object apart from natively supported Accounts, Leads, Contacts. It shows steps to be taken for setting up the Custom Object from SMS Setup. Kindly refer to this link to get the code as well as steps for setting up custom buttons: bit.ly/2oaX9Zn The video, as well as the guide, provides the step-by -step process that you need to follow for the complete setup for sending as well as receiving text messages from your custom objects in salesforce.