This is used to add links to the template page, the talk page and the edit page on to a template.
To use:
{{Nav|<template name>|<colour>}}
The template name is what follows after the "Template:". So for this template it would be "nav". For other namespaces, you need to include the full title, e.g. User:CJC95/test.
The colour is by default black. However, you can use any colour, by using the second field.