When running a home server, you always have to port forward through your router.
www.portforward.com has intructions for many routers and for your software most likely to help you port forward. Also, once the server is up and running, note that many ISPs unless you have a business account with them will block incoming Port 80, which is what web server software listens on. For it to work past your network, a site called
www.canyouseeme.org will, once you've forwarded the port and visited this site, will scan port 80 to see if it's blocked. If the port is open, you're all set to go. If it's denied or timed out, try a different port as your ISP is most likely blocking it. Port 85 is a good one to use, and in that case, you would need to set up a Port 80 Redirect in DynDNS.
Lastly, unless the web server software and the router is configured to do this, you will have to access your website via a network IP address (especially if it's on Port 80) on your network. Outside of your network you can use your DynDNS address, unless your web server and router supports using the DynDNS address inside your network then it's fine.