You must have an Arc.io account in order to do this. This will tell you how to install arc.io on Pterdactyl Panel for free
cd /var/www/pterodactyl/public
nano arc-sw.js
Copy all text from https://arc.io/arc-sw.js and put it into the arc-sw.js file. Use "Ctrl o" to save and "Ctrl x" to exit.
cd /var/www/pterodactyl/resources/views/templates
nano wrapper.blade.php
Put your widget script in the <head> element (in between <head> and </head>).
Your script should look something like <script async src="https://arc.io/widget.min.js#MyArcScript"></script>.
cd /var/www/pterodactyl/resources/views/layouts
nano admin.blade.php
Put your widget script in the <head> element (in between <head> and </head>).
Your script should look something like <script async src="https://arc.io/widget.min.js#MyArcScript"></script>.