Hi Tushar 

The counselling for 85% state quota seats is most likely to happen after counselling of  1st round 15% All India Quota (AIQ) seats.

In Some states more than 2 counselling are done to fulfil the seats and Mop-up round is organised if seats remain vacant after 2/3 counselling.

If you are intrested to take part in counselling procedure for state quota then then you should keep eye on official notification which will be published on state board website of respective state. 

Hope this was helpful.