When a foreign word is used in the media, journalists are normally advised to pronounce it as closely as possible to the original pronunciation, but using English phonemes. So when Real Madrid is said in the English-speaking media, the word Real (which means royal) is pronounced as two syllables and not like the English word real.
But journalists never seem to have got the hang of the name of FC Barcelona’s stadium. Apart from the fact that the words Camp and Nou are often switched round in the English-speaking media, the word Nou is invariably pronounced noo.
Some journalists realise this is not the correct pronunciation and try to pronounce it the proper way, but end up pronouncing it like the English word now. English speakers often produce the same vowel sound when pronouncing other Catalan words, like the name of the popular beach resort Salou. You even hear the same sound for Catalan words ending in eu, like Bernabeu in the name of Real Madrid’s stadium, probably due to influence from German, in which the eu is pronounced this way.
However, this ow vowel sound would be written au in Catalan, and appears in words like palau (palace).
The correct pronunciation of ou contains English phonemes, but it is the combination of phonemes that feels unnatural to English speakers. To pronounce the word nou properly, first pronounce the short o sound that appears in words like hot or cod. Now pronounce the sound written as oo in English, as in boo and coo. Now pronounce one straight after the other quickly, and you’ve got it!
Since this combination of sounds feels unnatural to English speakers, we could use a compromise pronunciation. But I would suggest the best compromise would be to pronounce the word nou as no, rather than as noo or now.
Finally, in the word Camp, the letter p is silent in the variety of Catalan spoken in Barcelona, although it is pronounced in some other varieties of Catalan.
If you’re still confused, why not listen to a couple of natives pronounce it.
And if you’re still confused, just pretend it says “Cam No”, as that’s a pretty close approximation.