In order to create a new content definition start the Windows Studio. Select a folder in which you want to create a new content definition.
Right click in the right hand list view. On the context menu select "Create\Content definition".
This brings up the main content definition editing view. In this view you should edit the name to be "HowTo". You should not edit the three fields called "Database table", "ID column" and "XML column" for the moment. For more details on these fields see
this "how to".