If you want it to work in the standard game, then put the pk3 file in your base, not gamedata. If you want to try it out first, then make a new folder in your gamedata folder and put the pk3 file in there.
That way, it shows up as a MOD under your setup menu, and you access it through there rather than it being standard when you start the game.
And Shepherds we shall be
For thee, my Lord, for thee.
Power hath descended forth from Thy hand
Our feet may swiftly carry out Thy commands.
So we shall flow a river forth to Thee
And teeming with souls shall it ever be.
In Nomeni Patri Et Fili Spiritus Sancti.
OMG Jedi Knight 4!!!