I want to take token from keystone and examine them by getting a lot of them.

i already got one token by using REST API as

now i want to get alot of token so i using Webscarab application as but i dont know which header i need to provive. i try to put Content-Type: application/json id_username: (myusername) id_password: (mypassword) but failed.

anyone know that, plz help me