2007 Liberty 2.0 Aux Install Help!?

[MrSammywammy]

Hey guys this is my first post.

I have just bought a 2007 2.0 Liberty with just the stock standard Head Unit (not Macintosh). I have realised that it has an AUX option available on the head unit but no input!?

I have tried to do some research but can't find anything that I really understand. I am quite savvy with most things and think I will be able to install something myself but I do not know what to buy!

Has anyone done anything like this? Please help as I WANT MY MUSIC!