Stupid question: Need help creating a cookie

Sorry for the rookie question. I have been working my way through magento for some time and managed to get 95% done with searching etc.

Anyway

I need to set a cookie for one of our stores, and have found this code:

Mage::getModel('core/cookie')->set(googtrans, /en/de, /, .domain.com);

Basically we want a cookie to tell google translate to stay in german for a certain domain. I have found no other way to do this easier.

So, I am quite lost on where to put the code, as I have tried various files that made sense to me and it doesn't seem to be working.

Any help very greatly appreciated, and thanks for reading