how can meet famous people at concerts?

[emm]

I want to go see one direction in concert, i live in wales so one in cardiff preferably. I know they're touring over here in january-february.. but can anyone send me to a website where they do backstage passes or meet and greets? anything i just want to know how to meet them here in the UK. If not, could i get there early or something? hmmm..
any information would be helpful:-)

thanks

[MELISSA]

go to their concerts