Thankyou very much for recommendations. I have already skimmed through developers website of documentation as well as looked at examples on github page infact I am used one of the example as my starting code for cvrptw.
The reason I am looking to understand the concept is currently I am blindly trying to apply stuff on google-or hoping it will work and give me the desired routes (cvrptw). Rather if I knew what was going on I could think and apply things or ask proper specific questions to optimize my solution to the problem.
This was the reason I set out to look for courses that explain VRP VRPTW CVRPTWs and use some kind of coding to explain further (google-or recommended).