changing real email address

[confidential]

I am a long time user of Trashmail and have a large number of trashmail email addresses forwarding to my current real email address with my ISP.

I want to change my ISP and move my primary email address to a gmail address. I have added my gmail address as an additional real address in Trashmail and made the gmail address the primary Trashmail address.

What do I need to do to get all the Trashmail email addresses that currently forward to my ISP email address to forward to my real gmail address instead of to my real email address with my ISP?