To take your site "live", you will want to add your own custom domain to an environment.
In aegir these are called "Domain Aliases".
In devshop, you can easily add additional Domain Aliases via the Environment Settings form.
Visit the Project Dashboard for the project you wish to launch.
If you don't have a "Live" environment yet, create one. Call it "live" or "production" or some other name that indicates that it is the live site.
Visit the Project Settings and select the environment you've just created as the Live Environment.
Click the Environment Settings icon icon on your live environment and select Environment Settings.
Check Lock Database to prevent anyone from destroying your live database.
Scroll down and add "Domain Aliases" for your live domain. Add both "yourdomain.com" and "www.yourdomain.com", then select one of them as the Redirect target. (using "www" as your main URL is recommended.)
Hit Save and wait for the environment verification to complete.
Add DNS A records to point to your devshop server for all the domain aliases you added:
mydomain.com. 1800 IN A 126.96.36.199www.mydomain.com. 1800 IN A 188.8.131.52
Once the DNS resolves to your server, you should be able to see your website!