Basically if you can enable homebrew to load on your ps2, you will load ulaunchelf and run the noobie package installer found here: http://bootleg.sksapps.com/tutorials/fmcb/
*This link in no way endorses piracy of any kind nor is responsible for any kind of damage you cause to your ps2. For the most part you should be okay provided you don't throw your ps2 in the bathtub.*
There are other ways. I think you can burn a disc with freemcboot to install from if you can't access usb for some reason. It was ages since I did that though so I don't remember. There are many ways though.