First of all Make sure you have Icon Packager installed..
THEN you can do 1 of 2 things.
1. You click the .ip pack and it should automatically be installed into Icon Packager.
or
2. Load Icon Packager. Click Install a new Package. Then Browse to where the .ip pack is and then select it. Then you click apply and it should be installed into Icon Packager.
I hope I helped and my advice was clear. I am free to answer any other questions you might have.
Enjoy! Icon Packager is awesome
I have most of the apps and enjoy them 