I've seen a bunch of people complain that goo manager wouldn't install twrp. I just went to the twrp page and downloaded the odin file and used that to install twrp. I wasn't sure which version of odin to use so I just used the one that came with the cf root which I believe was 1.85. You just open odin, plug in the phone, and flash. It was painless.
The whole odin thing is new to me as I'm an htc guy but it's pretty easy to use. Once you get a good backup out of twrp it's a lot more fun to play around with the phone. Mine has been a little temperamental to say the least.
Wife walks in...
Wife: Hey what are you doing?
me: Nada, phones finally rootable.