When you have a selection you should not click on the 'new channel' icon, the one that looks like a tiny page, but on the mask icon, the circle in the square. If you make a new channel all is not lost. If white is your background color (in the two large squares under your tools), press delete, if it is your foreground color, fill your selection. I think that if you read closely you should be able to follow the steps. It is pitty that I have a localized version of PS, so I have to guess some names and stuff... The misunderstandings could be the cause of that. My way is one of may ways, you can use other Adjustment Layers, or just paint over a black and white picture (with the document set to RGB) in a new layer that you set to 'screen' in the layer palette (or another blending mode) Have fun!