You should check your router to make sure it allows inbound connections and is doing any port forwarding correctly. You should make sure your ISP allows connections on port 80 and 443. If you have a firewall(s) make sure they allow inbound connections on port 80 and 443.
The latest guide you showed suggested using a hosting service. If you are going to pay for a hosting service you should look at one that makes setting up your blog easy. Let's Encrypt also has this list of hosting candidates.