Using Word web functionality on my website

I want to create a website where people can create new documents ,edit them on the web and save them in the site's database. I want to use office web interface for editing but I am not sure how to do it and if it's even possible. I understood that I need to somehow use office web apps server/sharepoint server but I am not sure exactly how to use it, and how to integrate the functionality of word web on my site. How can integrate office web on my website?

Thanks