I went through and did an entire setup for on premise SharePoint 2013 and how to integrate Yammer using the app in the SharePoint Store. This covers all the prerequisites such as setting up the service applications, configuring DNS, and then goes over the changes that must be made in SharePoint to replace SharePoint social features with Yammer features. Check it out: http://www.andrewjbillings.com/appsyammer2013/

-AJB