nectarine tree

Hope someone can help?  I've just been given a patio nectarine tree, it has blready been potted up, very kindly, and has ten fruit growing on it. I live i Northern Ireland so it has gone into the greenhouse.  I have never had any sort of patio fruit, any tips on how to look after it and how much to water etc would be gratefully received I am absolutely delighted with it and don't want to kill it!