How do I apply a gradient to a selection in GIMP 2.8?

[tbgg]

Hi all -

I'm trying to follow this tutorial and I'm on step 6, but I can't figure out how to execute it.

The instructions read

"6) Create another black filled layer named "Angular Fill". With our feathered selection, fill it with a Shaped (dimpled) gradient fill."

The image in the tutorial shows me the gradient options, and I've set those, but how do I actually APPLY the gradient to my selection? I can't seem to figure that part out. This seems like it must be pretty simple, but it's not intuitive to me.

Thanks all!

[Hustle]

Once you have the gradient tool set up properly, I think you just have to drag across the area of your mountains and GIMP will apply the gradient to the entire selected area(s). At least, that's worked for me the past few times I did this tutorial.

[tbgg]

Well, I at least see what I'm supposed to do now, and it's making a calculation, but nothing is changing, and I'm certainly not getting what he shows.

What I get before and after trying to apply the gradient is this:

The lines across there are political boundaries. I need 3 passes through the nation there in the middle, so I'm using those to help guide me as to where those need to fall.

Some things that weren't clear to me: In the previous steps, I used the lasso tool to outline where the mountains should be, then applied a blur to that area. Then I made a noise layer and selected the outline from the Blur layer and added the noise. Then it told me to make the Angular Fill layer where I'm now stuck. I'm not clear on whether I reselect the outline, then add the gradient (which I've been trying to do) or put the layer into overlay mode and use the outline from the Noise layer and fill that. But he doesn't seem to show that in the instructions, which is why I've been reselecting the mountain outline. He seems to assume we automatically know what we are supposed to do, but this is the very first time I've tried working with the gradient feature, and it sure isn't working for me.

Also, I need my mountains to zigzag a bit, but when I release the cursor, it goes straight into the calculation, which then doesn't change anything. Am I going to have to apply the zigzag strokes individually or is there a secret like holding down the Control key that will let me do all of the strokes in one fell swoop?