HELP: how to update 3.52M33...

I just upgraded from 1.50 to 3.52M33-1. Now I want to upgrade to 3.52M33-2, then 3.52M33-3, then 3.52M33-4. But each one is very hard to understand regarding updating. It's easy about copying the GAME150 folder, but what about this popstation business? It says copy seplugins to root of memory stick. Then extract the following prx of a firmware... What is prx??

Where do I get these files from:
/kd/popsman.prx
/kd/pops.prx
/vsh/modules/libpspvmc.prx
/vsh/modules/pafmini.prx

And the other updates has no installation instructions whatsoever....

Please can someone enlighten me...

you can skip update M33-2 and M33-3, and also you don't need those files to use it