If you don't know where to begin, it could be a long journey, I understand most people who attempt online business fail.
You can find a variety of paid tutorials that touch on internet business at Udemy.com and there are cheap member authored guides in the WSO section of Warriorforum.com a site emphasizing affiliate marketing, one of the easiest to start kinds of business one could.
You need a product or service first. What are you going to offer?
I have a small company and I have a website. However, the website is just a tool like other tools that I have. The real business is the service that I provide.
Starting the business is easy - making it a success is hard.
I thought of starting a website at some point, but there is so much competition already, I wouldn't really know where to begin.