To login you need to use an valid account who has permission to use the API.
Encrypting a plain text password
Link: https://au.itwocx.com/api/latest/api/help/index#!/Login/Login_EncryptPassword
Logging In
Link: https://au.itwocx.com/api/latest/api/help/index#!/Login/Login_ByEmail
By passing a valid email address and encrypted password you will receive a session key which can be used for all other interactions.
Using the session key
Link: https://au.itwocx.com/api/latest/api/help/index
Copy & Paste the session key received from logging in into the api_key field in the top right hand corner and click Explore
Once the page refreshes you can then use any of the interfaces, to for example retrieve a list of Projects.