What next?

Ok so I have the Pandora battery http://www.divineo.co.uk/cgi-bin/div-uk/psp-tools, I used roxfox64 MM installer... So what do I do next?
I have a PSP Slim OFW 4.01, how do I install 4.01 M33-2

Put the MM in, then put the battery in while holding up on the d-pad.

all i get is a black screen

It's supposed to be a black screen. I believe you press X

But you gotta wait until the WLAN and MS light stop flashing.