How can I redirect customers to a thank you page after opt-in using Postscript?

[cranullo0506]

Hi, Shopify community! We’re setting up a page using Postscript integration, to get customers to subscribe to our SMS list via an opt-in page. After they subscribe, we’d like to redirect them from the opt-in page to a thank you page. We’ve asked Postscript support for help on this, and they’ve recommended making changes to liquid theme files and adding code/hard code redirect in order to make this happen. First time trying to do anything like this, does anybody know what code snippet we can use? And how to implement this? Thank you!