By reading these forums. There is a ton of information, not to mention a ton of misinformation, all over the site. Just keep clicking on the headings and see what's within.
More seriously, though, there is really good information. You might like to try "Newbies Corner" and the blogs section for starters. As you come across the various methods, you can dig deeper by perusing many of the discussion threads on that topic.
There are so many possible ways, you will have to do your own research to see which suits you best. Nobody is going to do it for you. Anybody who claims they can is fooling themselves as well as you.
If you are prepared to pay for help, look up The DN Academy, run by Michael Cyger. That is the best known and most highly regarded formal training programme available.
There are also other sources of excellent information. DomainSherpas old interviews provided me with some excellent ideas and information when I started. Then I found
@Alvin Brown's "Kickstart Commerce", well worth trawling through and do sign up for his newsletter, which gives links to daily news and other newsletters.
There were more but those are what I remember best. Others may contribute to this thread with ideas, which will remind me of those early "tutors" I should be grateful to.
Welcome and good luck.