Passing ui-locales in the authorization request in a next.js sample app

Hello,
I am trying to allow multiple languages in my tenant “en” and “fr-CA” and I want the user to go to the corresponding NUL page based on the user’s opt.
I enabled the languages in the tenant, but I am confused with how to pass the ui-locales from the sample Next.js app (downloaded from quick start guides)

Thanks in advance