problems with writing posts

I am totally new to all this and have no idea of HTML. I do not even know what version of wordpress I am using.I write my post and it is all scrambled. I even tried writing in notepad and then copying and pasting and content in my post is full of spaces. I try to fix this by using mouse to start new paragraphs but this does not work. I’ve looked in forums and cannot find answers. Can someone help me by explaining in simple terms how to rectify this.