To use sabre flights booking module please follow below instructions
register your account with https://developer.sabre.com/user/register​
once your account approved you will receive the credentials
login to your admin panel and from modules go to sabre settings
in settings at paste your credentials and check your website results for test
once you are tatisfied with your development nd test mode please contact sabre and ask them to approve your daccount from test mode to production so your clients can book and generate PNR