Purchase from unregistered seller , where to show and how to claim itc

You can show in gstr-3b table-5

No GST applicable

Ok sir , thank you very much for the help . I have two more questions?

1. where to show supply to other states and what is IGST? ( i am from west bengal) 

2. I have purchased item from a registered seller who has only filed gstr 1 till now but not 3b . I file on a monthly basis so the transaction was showing but ITC was not available . I have put the itc values by myself and claimed itc . Now balance is showing in my cgst and sgst . Have I done anything wrong . It yes then how to correct it when my supplier files gstr 3b and I get double input tax credit?

GSTR-1 deal only with sales so no purchase details will be provided in GSTR-1

GSTR-3B TAble 4(E)  deal with availmemnt of ITC on Purchase

Purcahse from URD seller would not have GST in Invoice. Therfore no question of GST ITC claim arise