Templates usually end with a .vm

See the official velocity website for downloads and documentation. The Velocity template language reference guide holds quick syntax information.

Velocity syntax notes - cheat sheet

Code snippets

for each loop

#foreach($passenger in $booking.passengers)
first name: $passenger.firstName
passenger number: $velocityCount
#end

In the above snippet, $velocityCount starts at 1, according to the user guide you can alter this to start at 0 or 1, and you can also alter the variable name.