Hi B.! I just potty trained my youngest child about a week ago (she is 2.5) so the process is still fresh in my memory. What I did with her was to wait until I thought she was ready to do it. By that I mean, she is not quite as "terrible" of a terrible 2 as she used to be - she is fighting me less and less on every little issue. I think potty training a child who is going through a very negative phase just doesn't work!
Anyhow, so once I decided she would be ready, I took 2 days off work before the weekend. (Or if you can't take off work, whoever watches him during the day could do this.) I told her the day before, "Isabelle, we have run all out of diapers! I don't have ANY more! So tomorrow you will have to use the big girl potty." And then the next morning, I actually let her run around without underwear or diapers. (At first she cried and begged to have a diaper on, but I stood firm that we were ALL OUT!) With her bottom bare, she could feel immediately if she had to go to the bathroom. And I just kept on her every 20 minutes or so until she went in the potty. I offered her lots of water and juice so she would have to go a lot, and then would really heap on the praise whenever she would go in the potty. We had a few accidents the first couple of days, but by day 4, she stayed dry all day! (With the accidents, I tried not to make a big deal of it except to say, "oops! Next time when you feel like you have to go, run to your potty!" When she went back to preschool the next day, she did not have any accidents either. (Not even during naptime, which surprised me.) I still do put a diaper on her at night. For me, the real key is the bare bottom - for some reason when they are first learning to use the potty, underwear can confuse them into thinking it's fine to pee-pee or poo-poo there. But with the little bare bottom, they don't want to pee on their legs so they make it to the potty.
With my older daughter, potty training was much easier. The day she turned 2, I told her that going pee-pee and poo-poo in her diaper was yucky, and pointed out that mommy and daddy do not wear diapers, we use the potty. Then I showed her the potty chair, took off her diaper, and I swear the child potty trained herself in about 4 hours. (It's like she was born 40 years old though, that's just how she is.) So you can imagine my surprise when that didn't work with child #2, LOL!
Anyhow, good luck in your potty training adventure! It is hard at first but you just have to stick to it and let your little guy know that there's no turning back! He will be so proud of himself when he is using the potty and is a "big boy."