Its a public domain model/software from USACE. They have nice tutorial file and manuals by trying this, you can learn by yourself.
If you face technical difficulties, i think there are many in this group to guide you to overcome those.
I think you dont need to go to a coaching center to learn this. Although I did not work on HEC-RAS, but I worked on their HEC-HMS and HEC-ResSim software and i learned by myself based on their tutorial files and manuals. The manuals are so nicely written that even a novice in modelling can understand each and every point easily. They even provide a technical manual to understand all necessary details related to the technical terms and equations etc.
Best of luck.