Hello dear,if you will be alloted a seat in second round then you will have to pay admission fee and also you will have to physically report to the reporting centre as per the schedule.Keep ready all the documents like 10th,12th marksheets,category certificate(if any),Score card etc.These documents will be verified first after that only your seat will be confirmed.The second round allotment will be on 9th July and you will have to report from 10th July.So be ready for that.

Check this link for complete schedule of counselling https://engineering.careers360.com/articles/wbjee-counselling

Thanks.