Exchange a SAML assertion for a Quickbase token

Hello, I am looking to use a SAML assertion for authentication of a custom web app that uses the QB JSON API.  In the linked documentation, it is described that you can use an API endpoint to do this, thereby authenticating your app using the currently logged in user with a SAML assertion exchange.

But the documentation is super vague and provides little for one to go off if you are not a SAML expert.

https://developer.quickbase.com/operation/exchangeSsoToken

The line from this documentation I linked to that I am focusing on, is this:

You must be able to create a SAML assertion in your code to use this endpoint.

Does anybody have documentation or advice on how to put the SAML assertion together?  I want to link to my app from Quickbase using a Formula URL.  Then I want my app to authenticate the current user so they can perform some tasks in my custom app under the same identity they were using in the QB app.

I would love to see a full example, code and all, to help with this.  (Minus any secure pieces you need to obscure.)