Hi, 

During the all India quota or state quota counselling form filling you will get there a option for ews category you have to choose that option in the form.they can even demand your family income certificate to be scanned and attach to your form. 

On the basis of that you will get 10% reservation as the board of governors has ordered. 

You can get your ews or family income certificate prepared in the nearby government office who prepare it . 

For any other query you can ask us.