Hello aspirant

RUCcode is registration of unique code. If you could not generate r u c code then you have to to visit http//mdmsmch .aiimsexam.org/#! Website and login with your credentials. If you have application is accepted then they will send a message in your mobile or email. Then you have to to create create RUC code for further process. If your basic registration is complete generate your RUC code will be displayed on the screen. Select the option and verify the details and come and complete the RUC code in which  your registration will be complete.

On the other hand if you could not register yourself with RUC code registration then whenever the AIIMS authority will open the option for generating RUC code then you  have to login in for  RUCcode to complete your registration.