Hi, yes it is compulsory to apply for cmc vellore seperately it takes admission from neet scores but there is seperate application form for getting admission in cmc vellore.Application form filling takes place in February and in june after publishing of neet results site opens and neet score filling takes place and after that merit list is prepared. All other information regarding it is in the link

https://www.google.com/amp/s/medicine.careers360.com/articles/cmc-vellore-mbbs-admission/amp