Help With Downloading Roms

[ppcwannab]

I apologize for posting this thread if this info can be found elsewhere. I need some direction regarding downloading new roms to the Touch Pro (Sprint). I have researched the forum trying to find my answer. I followed the flash tutorial provided (great info) however after unlocking my device and attempting to upload the new rom i ran into some issue. I am a noob at this so please be gentle..lol. The rom i downloaded is the new MightyRom however the file typ is a .rar and the tutorial says i need a .nbh. Am i supposed to convert this file or have i done something incorrectly? PLEASE HELP!!!! Again if this info is available somewhere else i apologize i tried researching this for hours last night and my eyeballs are bleeding buit i still cant download the ROM. Please point me in the right direction.