Hey Chinmoyee,

For applying in a government college for Physiotherapy course (BPT), you just have to fill the application form for the particular college which you want through online mode or any other mode as per University.

Just fulfill the eligibility criterias for the course and go for admission. 
Eligibility criteria for Physiotherapy is that you must have passed 12th examinations with Physics, Chemistry and Biology as compulsory subjects and have scored minimum 50%marks in the qualifying examination.
The admission can be given either on the basis of merit in qualifying examination (12th grade) or on the basis of entrance exam conducted by the university itself.

Good Luck!