Check out these links.
http://wiki.dreamfactory.com/DreamFactory/Tutorials/Logging_in
http://wiki.dreamfactory.com/DreamFactory/Tutorials/Logging_out
http://wiki.dreamfactory.com/DreamFactory/Tutorials/Access_Using_API_Key
http://wiki.dreamfactory.com/DreamFactory/Tutorials/Access_Using_JWT
http://wiki.dreamfactory.com/DreamFactory/Tutorials/Access_Using_JWT_and_API_Key
http://wiki.dreamfactory.com/DreamFactory/Tutorials/Refreshing_a_JWT
http://wiki.dreamfactory.com/DreamFactory/Tutorials/Forever_sessions
http://wiki.dreamfactory.com/DreamFactory/Tutorials/Using_Forever_Session