HOW TO PUT FINS IN A SURFBOARD?

There are many different types of fin systems available. 

The two most popular systems are:

•  FCS 
• Future. 

Understanding how to put these fins properly on a surfboard is a basic, 
yet essential skill. 
This short video will walk you through fastening FCS, Future, quad and longboard fins to your surfboard.

...and now let's watch another video:

The source: http://blog.surfride.com/how-to-put-fins-on-your-surfboard/