Reverse charge paid in wrong tax head.

Hello,

I filed my gstr 3b for May where I wrongly paid reverse charge in cash as cgst and sgst instead of IGST.

I also didn't fill the space where I need to claim input for same.

Now I'm going to file quarterly gstr1 and want to rectify the above.

As far as wrong payment is concerned, I heard that I need to pay tax in igst first and claim refund for cgst and sgst.

However, how do I claim input afterwards? also how do I need to file gstr 1 to reflect changes.

Thanks in advance.