Battery problem

Hi
Iv'e just bought a new battery for my disco, I put it on but because there is still a few jobs to do to get it onthe road. Now after a few weeks of sitting idle the new battery isn't starting the engine. It isn't lighting the instrument panel it was that low. I tried to jump start it with a power station booster but that gives it enough power to light the instrument panel but not to start it. Why is this and what should I do
Thanks

Batteries aren't supplied fully charged, and the booster probably didn't give it enough power. I'd disconnect the battery and give it an overnight trickle charge. Or bump start the vehicle and leave it running for a while or take it for a drive.

Nice 1 I will charge it up