Play Pokemon on HTC evo helpppp?

Okay, i used to have this all downloaded and fine. I got my phone erased. So lets try it again. I downloaded the GBA emulator. And I guess i forgot about the BIOS. For some reason they are more difficult to find. Whenever i find and download a BIOS bin file, i go to the emulator and it says that "the bios is not specified in the settings". I go to settings in the app and it is there but i dont know what to do with it. I remember in the past i had downloaded the bios, app, and rom gripper and was fine. Why is it so confusing? Can someone PLEASE give me a very detailed step by step process to get this on my phone? I am electronically challenged :/