I hope this is the right forum. If not, I won't take offense to an admin moving this thread.

I've never used mapping software in my life. I've drawn many RPG maps by hand, and I've used equations to generate a "map" with computer software for me for the purposes of physics, but all of this is so new to me. I have a very scientific backround and not much of an art one.

So I figured the best place to start would be one of the basic tutorials on this site, go through it, and figure out why I'm doing the things the tutorial says. When I can do it, I get why I'm doing it, but I can't always do it. Currently I'm working through RobA's tutorial, "Using GIMP to create an artistic regional map." I'm using GIMP 2.6.6.

In the four part pdf file, I'm stuck on the first part somehow. A few major hangups...

First I downloaded and imported the palette he provided, but I'm not really sure how to even use it. The palette editor is different from the one pictured in the tutorial. This is probably the simplest question, and to be honest, I haven't even gotten to the point where I need the palette, but since I'm making the post... If I need a color from the palette, I just click on it?

Second, I drew a rough map in paint for my coastline. He says add a new transparent layer, name it "Land" and trace the path of the coast. Then, go to Colors -> Invert. I ran through this part 3 times, and only once was that option available. The other two times, the invert option was greyed out. I can't figure out what I'm doing wrong. I did get it to work, but in the interest of learning, I'd like to know WHY it didn't work.

Third, on pg 14 of the first part of his tutorial, he creates a new layer called "Sea Noise" then merges it down with the "Sea Shape" layer. Then he duplicates this layer and renames it "Sea". Then he adds a layer mask and tells me to select "channel" and it should by default list the "Land Mask" channel. The problem is when I go to this menu, the channel select box is greyed out and I don't have the option to choose anything at all. For what it's worth, I only have a vague idea of what layers, masks, etc. are at this point. Can anyone explain why the box is greyed out?

I know I sound silly with all this, as most of you folks have worked with this software many times over, so I appreciate any and all replies in laymens terms. I've only tried to start using this stuff in the past week, and it's a bit overwhelming at first. So far, of all the tutorials I've found, they are either extremely simple or using terminology that I don't know yet.

Thanks in advance!