Velocitoro is generally based on Velocity. When you create your web site you have files that are copied verbatim and have files that are processed by Velocitoro. These files (which have a shadow file, that bear the same name and the extension .vm) should contain Velocity macros.
Because Velocitoro uses Velocity you have the full freedom of Velocity macro engine to define macros, include other files using the velocity command
#parse( "otherfile.vmi" )
Generally you will have pages that are similar and have some parts that look the same. You will gather these page fragments into .vmi files and define macros to generate the page fragments. There is a detailed and complex example how to create a navigational bar using velocity macros and Groovy.
To get acquainted with the ideas and the technic have a look at the HTML templates of this project and the play around with them a little.
In the macro files you can have access to two objects. One of them is called $groovy the other one is $date. The $groovy object is used to call Groovy scripts, while $date is to access the Velocity date tool.