How to call a function in CI

[eluser]masentinel900[/eluser]
I did viewed that CodeIgniter Is only POO.

In the POO I need to call a function for that this runs. That will be like this:

<code>
$something -> name_function();
</code>

My problem is that I don´t know how to do for to call a function.
If a have more than two functions and I need that these works at same. How I can get it?