PHP - Set current user token.

Hello! I am trying to achieve session persistence between pages and I was following the suggestion detailed here:
However I could not find a PHP function to set the user token to the value I successfully have stored in my cookies. How do I set the current user from the token?

I have the same problem, I redirect in php to another page, but CurrentUser is null…

current user is not carried over when you do a page redirect.