Create two “A-records” at your DNS provider for www.yourdomain.com and yourdomain.com that point to 184.108.40.206. (You can also do the same if you’re using a subdomain, of course.)
The exact method for creating A-records is different depending on your domain registrar and DNS service.
Once you’ve created the correct DNS records, add your domain to the Blog section of Settings. Type only “yourdomain.com” or “blog.yourdomain.com” (don’t add “www.” or “http://”) in the “custom domain” box.
If you’d like HTTPS support, which is in beta, please email us and we we'll enable it for you.
If you need more help: firstname.lastname@example.org.