Open the link - https://trueconnect.jio.com/#/. The below show page would appear.
Click on Principle Entity and then select New Registration as shown below:
In the page shown below, if you have NOT registered with any other operator, select No and proceed
In the page that appears, as shown below, fill in the details and upload the documents requested.
Once done, click submit and you should receive an acknowledgement as shown below if all the details are correctly entered.
Two emails will be received post this, one for the acknowledgement of the registration competition and another one is for successful confirmation of registration. In case there are any concerns with the documentation, then an email with rejection details will be shared, at which point, re-registration is required.