I'm going to break down a few of your questions.
Layers, Layers help you organize your graphic. Also the more layers you got, the more "Tweaking" can be done.
Layers allow you to blend stuff that normally can't be blended in a normal picture. For Example, If I slam a this wierd awkward Blue thing onto my black BG, I can use the layer settings, and change my blue thing, to Soft Light or something and it'll be like a lighter color and stuff on the black BG.
I suggest to help you with this, choose a Black Bg. Create a new layer. Find a small pic and place it on the Black Bg. You should have a Layer window available, if not, goto...
at the top of your screen Window>Layers
Usually it appears somewhere, most frequently for me the bottom right. When you see the layers in the small box, above it is some tools, you do not need to click any of them.
There should be a "Opacity" setting, a "Fill" setting, and to the left of those a box saying "Normal" with a menu arrow. On the little picture layer, click on that arrow, and click one of them, and it should turn blue, then use your scroll mouse button to look quickly at some of the settings. Try screwing around with them.
A White line, with black bg, glow really light, odd question, but nothing comes to mind for now, sorry.
I'm trying to think that you want to do this....
In your tools, most likely the top left, there should be a rectangular marquee tool. Right click that for a horizontal marquee that goes across your entire image. Then like the Border technique, goto edit>stroke, do 5 pixel white. Right click the layer, hit blending options, use a drop shadow, and up the settings with Opacity to 100% and the size a bit bigger. Then goto Outer Glow, and amp up the settings there. This isn't a great thing to use anyway. You'll find out this question is useless.
The text solution is...
Dafont.com and google 22pixels(I don't remember the exact name). Sometimes DeviantArt provides some stuff.
When you download a font file, usually it's a zip file, place it in C:/Windows/Fonts (I think)