I'm looking into render passes but making zero progress.

It's a single frame image I'm trying to render and it seemed an ideal time to tackle layers and passes... I've got as far as batch rendering a layered PSD, which seems ideal, but I'm stumped when it comes to passes. I've created a layer with all relevant geometry and lights and created a few associated passes... but get nothing in the PSD layers.

Every tutorial I've watched goes about things in a different way - some create individual layers and change the attributes, some use contribution maps, others seem to simply do as I've done. Many of the tutorials seem to be geared to creating 32 bit files for use in Nuke or similar - I just want a PSD file to manipulate to create a single image.

I'm at a loss to know where to start solving this....

thanks