Rom manager lost my sd card

A

AC Question

Hi I'm new to phones so this is all a bit confusing. I have a Samsung galaxy s3 and i routed it some time ago and put CM on there. I now want to put Boeffla kernal on to run better sound so I opened Rom manager and was guided through some steps to download something. I was not really paying attention as it said it was an update but part of it took me to a screen that asked me to tick a box with some reference to access and the camera. It seemed a little strange but I, no nothing about this stuff, went ahead and it said you are now ready.
I then rebooted into recovery and realised my kernel download was on the phone and not the sd so I rebooted and went looking for the file.
I plugged my phone into my PC and got a window I recognised about the camera thing again asking if i wanted to keep this and said yes as it seemed that the rom manager wanted this way. But now the sd card dose not show on the PC and the little picture of a phone has been replaced by a little picture of a camera. I tried looking in file manager but cant see my sd card there either.
I tried playing music from the sd and it's all there and fine but just cant see it anywhere. I tried unplugging and re-plugging my phone to PC but never got the dialogue box again. I searched through everywhere on the phone but can not fine this option i was offered by the rom manager anywhere.
So now I cant move the kernal file to the SD card and cant find my SD card to access it in any way. I tried searching online but cant seem to find anything anywhere. Can anyone help?