Using Oauth correctly

I'm working on using Troop ID to verify that a user is a veteran on one of my sites. I have an account with them and dug through the developer docs trying to set up something simple with their sandbox. They are using Oauth. I got the button on my site that users click which takes them to Troop ID to verify, and using a test account I successfully verified. It then takes me back to another page I set up and appends code to the URL. Here is where I'm stuck. I don't know where to go from here. The Dev Docs say "Once the user has authenticated and then authorized your application, we’ll redirect them to your redirect_uri with the access_token in the url fragment. It’ll look like so:


Simply grab the access_token off of the URL fragment and you’re good to go. If the user chooses not to grant access to your app, you’ll receive the same error response as in the server-side flow."

I do have an email in to Troop ID, but don't expect anything back until Monday from them, but I figured that the Dev's in here are amazing at putting things simply so I'd ask.