This is applicable only to OpenVZ based VPSes. For KVM based VPSes you can configure the whole range on the VPS network interface and use as needed.
First, Login into CrownPanel (https://crownpanel.com)
Then, Click on "Manage" beside the VPS you wish to manage
Next, Click on the "Manage Network" tab
After that, Click on "Launch" under the IPv6 Wizard
Now, You can add your IPv6 from here