How to use functions in template

[ZomgStuff]

How do i use a function like this

function fetch_userinfo(&$userid, $option = 0, $languageid = 0)

in my own template, one that I'm making following this guide
https://vborg.vbsupport.ru/showthread.php?t=62164&highlight=create+your+own+page

Well an easier question, how do I get it to run and not show up as text?

The page just displays this

fetch_time_data();

[Kungfu]

you can assign a variable such as

$gettime = fetch_time_data(); and in your template just put $gettime.
As far as running the the function after you load the template you cant do that as it should be run in php and php is serverside, running it after loading the template would be clientside.

[ZomgStuff]

Thank you.