Noob stuck on HTTP Request Tool

Hey all! I just started using N8N and I really like it. I was able to build out a simple flow that accessed Tableau via the API, pulled out the list of workbooks, pulled the view I wanted, and then converted the data to a CSV.

But, when I tried to switch to using the AI Agent and using expressions, I am running into some blockers. I have OpenAI Model, Windows Buffer Memory, and two HTTP Request tools attached to the AI Agent. The first tool is to authenticate. I have a Personal Access Token setup and that works fine. It pulls back the site ID, User ID, and Token without issue.

I am confused on how to use that information moving into the other HTTP request tools. I am not a JSON expert, but I have been managing until now. I am not sure where the info from the authentication is stored or how to pull it into the next step. I was trying something like - {{$json["response"]["credentials"]["token"]}} for the token in the header. I tried {{$json["response"]["credentials"]["site"]["id"]}} for the site ID in the URL.

I feel like I am overlooking something simple. Any suggestions?