Welcome to Linux Questions!
You'll need to tell us which HP printer you're using (probably)
I'm running Linux Mint 17 with an HP Photosmart something-0r-other. I powered up the printer till the WiFi blue led came on to say it was connected to my lan then I just added a network printer via the printer application on Mint, it picked it up straight away, set as default and Rober et votre Oncle!
You should probably have the hplip
driver installed by default in Mint. (I can't remember adding it but it will be available in the repositories if it's not.) Your printer should be supported, check here
Let us know how you get on.