deviangel wrote in post #15099452
How wouls the screen show me if they are underexposed
The most obvious is that the image would be dark. Another way is to use the histogram - that's the image that looks like a graph. Read the owner's manual to learn to use these tools. However, even before you took the image, the meter on your camera should have told you that the image was too dark. Do you know what mode you were shooting in? P, Av, Tv, M, etc?
deviangel wrote in post #15099457
The problem is simple I suck in taking pictures

I don't think you suck. Photo # 2 is nicely composed and captures a very interesting image. It's easy to learn the technical aspect of photography. It's much more difficult to learn the artisitc side. I think you understand the artistic side from your compositions and subjects' faces, you just need help with the technical side.