In the top navigation bar, go to "OAuth Clients". This page displays OAuth Clients you have created. To create a new OAuth Client, click the "Create App" link on the left navigation panel.
Give your application a name and use "https://httpbin.org/get" as the callback url. Note down the client_id and client_secret. You'll need them later on.
Fill in the client_id and callback_url below, then copy and paste the link to your broswer
Provide your credentials and grant access to your OAuth Client
You will be re-directed to httpbin.org, where the response will be shown to your broswer
Note down the code under the args section of the JSON payload
Fill in the fields below, then copy and paste the URL into your browser again
You will be redirected to httpbin.org, and the JSON payload should display your OAuth token
Store and use the access_token value to access the API endpoints.