T & D Electricals

1. Whether separate registration is required in Karnataka state ? If yes, whether agreement would suffice as address proof since nothing else is with the assesse and service recipient will not provide any other proof?
2. If registration is not required in Karnataka state and if we purchase goods from dealer of Rajasthan and want to ship goods directly from the premises of dealer of Rajasthan to township at Karnataka then whether CGST & SGST would be charged from us or IGST by the dealer of Rajasthan ?
If registration is not required in Karnataka state and if we purchase goods from dealer of Karnataka to use the goods at township at Karnataka then whether IGST would be charged from us or CGST & SGST by the dealer of Karnataka?
3. What documents would be required with transporter to transit/ship material at Karnataka site from dealer/supplier of Rajasthan and in case of dealer/supplier is of Karnataka. Advance ruling may kindly be issued in case of registration is required or not required in both the situation?