lanyards: Hi there. Sorry you can't follow the instructions.
You are nearly there. To copy and paste, Select > All (Ctrl+A). Edit> Copy (Ctrl+C). back to the Channels tab. Click onto your new Alpha 1 channel . Edit > Paste (or Ctrl+V)
- You don't need to click on the 'save selection as a channel', but you use the 'Create new Channel ' next to it.
Here's a more detailed walk through...
1: First make sure your artwork (your B&W alpha map you post here ) is in the right color mode. Image >Mode > RGB color
(It sounds like you are, but I copied your map to my PS to check and it was grayscale, which I'm guessing you changed it to for the sake of putting it up here, but just wanted to check)
If you don't have it as a RGB image, then some of the tutorial may not make sense. All you would see in the channels is 'Gray' and no RGB that I mention. If this is so, perform the step above first.
2: In your Layers tab > L click with your mouse on the Background layer and drag it to the new layers icon. It will create a copy of your B&W image above your Background layer called 'Background copy'. This is not yet technically an alpha map until it's in the channel tabs. it is currently still just a B&W looking image.
Note: step 2: (on this post) is not absolutely necessary for what I'm explaining here, but I think I use the background copy for other stuff later in the tutorial
3: Now click on your Channels Tab. You should see 4 channels: RGB, Red, Green, Blue. They will most likely all be selected. You can click on them one at a time to see how they effect the layer.
4: While still in the Channel tab, L click with your mouse on the new channel icon at the bottom (next to the trash can - looks like the new layer icon from the layer's tab). You will create a new channel, which will name itself as Alpha 1 as default. It will probably be the only channel visible (the eye icon) and will be white, because it's an empty channel.
5: Click on the Layers Tab. click on your 'Background Copy' layer. Select > All (Ctrl+A). Edit> Copy (Ctrl+C).
6: Click back to the Channels tab. Click onto your new Alpha 1 channel . Edit > Paste (or Ctrl+V)
7: You can test if it's working by Ctrl+L click with your mouse on that Alpha 1 channel. It should now select only the black & grayscale areas.
(You can rename your alpha channel if you prefer by double clicking on 'Alpha 1' once it is active and type in something else. The same method for renaming the layers )
You should now have your image in the correct alpha channel. Let me know if this helps - or not.
cheers
Jez