Install the font first before use.
How to install font
windows :
https://www.fontspring.com/support/installing/how-do-i-install-fonts-on-my-windows-pc
mac :
https://www.fontspring.com/support/installing/how-do-i-install-fonts-on-my-mac

FOR FULL GLYPS AND COMMERCIAL PURPOSE:
http://saridezra.com/product/callistera-signature-script-bonus/

You can also buy it on Creative Market:
https://crmrkt.com/OwWVpB

Thank You,
Sarid Ezra - www.saridezra.com