Hi, welcome to phpBB.com!
We have quite a bit of documentation available
on this matter so you might want to have a go yourselves first. Feel free of course to ask any questions you might have here on the support forums.
We do however, per our board-wide rules
, not allow solicitation of people for your own personal projects here on phpBB.com. If you still want to hire someone to do the work for you, we usually recommend for you to look at the signatures of team or community members. Many of them have a line saying you can contact them via PM for (paid) private work. You're allowed to contact these people if they have stated so.