Have a look at
should answer your questions - especially if you view the
Thanks, Sam. If I am right, I have to create the page
Template:Yes on my own wiki. If I go to that page, mediawiki
proposes to create the page, like any regular page. Though on
Wikipedia the label of the first tab is "template".
Do I have to "activate" the template namespace in any way?
Also, to install several templates listed on the above
Wikipedia page, do I have to create all templates by hand, one by
one, or is there any kind of install process?