Suppose you have the OAuth2 ACCESS-TOKEN and your USER-ID, you can simply use HTTP GET requests to obtain this information.
In order to get your user info, you need to perform a GET request to the following URL:
https://canvas.instructure.com/api/v1/users/<USER-ID>/profile?access_token=<ACCESS-TOKEN>
In order to get course id for the list of courses you belong to, you need to perform a GET request to the following URL: https://canvas.instructure.com/api/v1/courses?access_token=<ACCESS-TOKEN>
For more capabilities you can use the following API documentation:
https://canvas.instructure.com/doc/api/index.html