Shram suvidha portal - I have received LIN number. What I am supposed to do?

I have received LIN number. What I am supposed to do with this portal. I have never used. Pl inform if there is any legal action.

login to the portal and submit verification, under ESIC/EPF/PAN/CIN/CST and other verifier details, also NIC code of the goods or service, and contracter / contractee details ( if any)
after your submission it will take some time to get verified from respective departments,
soon the ESIC/EPFO combined returns are going to be filed through shram suvidha portal, through LIN number

You need to file the annual return from that portal for fy 2015 and 2016. So go to annual return tab and do as follows Shram Suvidha Compliances & Explanations

You need to log on to the portal, review whether the Establishment information mentioned therein is correct, if there is any error rectify the same. You have to submit returns under various labour laws applicable to your Organisation on line and then upload a verified authernticated copy on the portal.

please let me know
It is mandatory to register for principle employer under the portal and obtained LIN. or third party vendor registration is enough.
Note : Principal employer doesn't have any direct labor.