Oooh god, this is so awkward. While typing my answer in here, I just figured my problem was to totally overcomplicate the issue. :’D
I did think, I’d need to setup a page to ehich I’d need to assign a custom template, which contained the abovementioned code!

But actually I just needed to create a normal page and put the code in text-view – and voila.
I’m sorry!^^#