How to access session token with next-auth in order to attach it to a API request header?

Question

Hello I'm new to NextJS and React, but my project currently has a 3rd party api that I'm working with that requires a session token input in the header for all requests.

So I picked next-Auth for authentication but I have problem accessing that chunk of raw jwt.

I tried useSession but it only gives me info within JWT (users, expiration, etc). I found a server side function in documentation called getToken() but the sample requires a line like this:

const secret = process.env.SECRET

Does that mean i need the secret key to the jwt signature in order to retrieve the raw jwt?

I can see that session token in my cookie under my localhost file and I tried to use js-cookie to get() that cookie, but I still can't get deeper to get the inner cookies. I wonder how I should approach this problem and what's the proper way to attach session token in API requests for next-auth setup.

Thanks!