Howto create Glue records:

Log in to your account. 
select the domain you need to create glue records for.
under management tools select "register nameservers"
here you can create nameservers, update or delete them. 

Notice, there are not all of TLD that allow creation of glue records ( name servers ) 



If you are unable to create glue records to your own name servers please create a ticket to support and we will create them for you.
Please add domain and ipv4 / ipv6 address that you want to create.