1999 Mercedes Benz ML320 Battery issues

Our old battery was recently replaced with brand new one (car doesn't get driven often). Now it's completely dead, nothing comes on, lights or anything. We put on the battery charger for several hours. Now the lights and accessories now come on but it still won't start. Should we charge more or try and jump it? If and when we get it going how long do we need to drive it or do we to charge it up? A friend said new batteries are not really intended to be put in a car that sits a lot because they need used and charged a lot when they're new to "build them up". Is this statement true?
Thanks!