Hello Ratnadeep !!

Congratulations on getting a college .

Yes you have to submit your documents at GMC,Chhindwara so that you can lock that seat.

Since you want to apply for upgradation, you can put yourself under float option . If you get upgraded and want that college , you need to write a letter regarding your documents to GMC,Chhindwara so that you can get them back.

All the best .

Hope this helps.