Help with plutonia 2

Hi there. I don't know if this has been asked before, I didn't found anything searching the forums. The thing is, I dowloaded plutonia 2 and it won't run in prBoom 2.5. In the text file it says that I must select the plutonia experiment as the iwad. This might explain the problem, it's just that i don't know how to do it. I've tried almost everything, from the text files in the prboom folder to the in-game menu, and I still have no clue of how to do it, and I feel really stupid, I mean, it's something everybody knows apparently. Any help will be very much appreciated.

Nevermind, I found it a couple of posts below this one. I'm so sorry, maybe an administrator could delete my stupid post?

Just close it, admin options, bottom right.