i guess you know that you need a very slow shutter and a big aperture. as you can see he turned the ISO very high (the 5D has an excellent noise reduction built in) and i guess he did some post productions. you have to shoot RAW files because there you can get out the most of the information of the pictures. for instance you can use the curves to turn up the light parts (which are only given in the stars) and increasing the contrast (which will boost the stars as well). but as always: try, try, try. try everything, experiment and sooner or later you'll figure it out yourself (and if not: there are tons of youtube videos ) good luck!