I’m wondering what exactly did you mean by “So far PW doesn't seem to work on this webpage”.
When I want to add custom behavior to pages, I start with a JS snippet like this:
console.log('I am executed');
Save PW settings, open the console in the tab with the page I’m trying to customize and then refresh it. If I don’t see my message in the console, I have probably messed up the URL regex. If I see the message, I know I got a good start, and I start adding more code in small steps and carry on with the “console.log debugging”. :)