I need help! selling an eBook online

Several years ago, I learned html, css and a little javascript, which btw javascript certainly isn't my strength. I built a simple website that had general topics articles and tips. I also had advertisements on my website through one of the affiliate marketing firms. My knowledge was perfect for what I was doing at that time.

But now I have finished my education in a field that has nothing to do with web design and I want to combine the two fields. I have written an ebook that I would like to sell on a website, but I do not know how to publish it.

I do not know what code to use to offer the download, what software is needed, basically I haven't a clue where to start or what to do. Basically, I feel like I'm starting over from scratch.

Any information would be greatly appreciated.

Thank You