You need the PRO version to do the following.
Let's say you have your own website called www.example.com and want to use your domain instead of paperturn.com.
Most likely you are using www.example.com as your normal website. You should then create a CNAME called publication.example.com, brochure.example.com or whatever you prefer.
In this example we have chosen publication.example.com.
You need to create a CNAME record within your own domain DNS service to route queries for publications.
The CNAME needs to point to www.paperturn.com.
Example from godaddy.com
If you have possibility to insert TTL, just ignore it or insert default value.
Please notice that it can take from 1 minute to 6 hours before the changes from your DNS host are active.
Wait one day before inserting your new CNAME in Paperturn. You want to be sure that it is active before use.
Afterwards please login to paperturn.com, go to one of your flipbooks and click "Edit".
Now you can type in your selected CNAME.