Clear pictures - help requiered

I have a Gimp version (2 point something) but i  dont know what to do in it . Those layers and all that information blurs me more than anything you can imagine. I have no idea what to do with it. The most frustrating thing is that i truly have an amazing camera and i am trying my best to show its real value and it took me a while to understand that is not my camera that needs "adjustments", it is me ...only i dont know where to start. I know i need to practice a lot and this is the reason why i made an account here so i can learn from all you great photographers.

And thank you so much for all the help and advices you have given me. They are really useful.