Trying for Months

Ok, so this might be the easiest way to find some help. I am not program friendly and I have tried about a hundred times now. I want to change my blog to a 3 column. And I also want to change my blog background to a custom one. I located some elements that I want to use but once I get into the Paint.net program, well let's just say we dont' work well together. I will try one more time this weekend at home with hubby. He has Powerpoint on his computer so I'm hoping we figure it out on that one. But if not, HELP!!!!!!!!!!! The Free ones are nice but not my style. I really really would love to learn this but I'm frustrated. Thanks for reading. Pass along if you could.