Reference "File" from "For a selected Item" in SharePoint

Hi Leonel GUZMAN please refer the image and the steps below

1. For a selected item you will be able to receive only few information, so you have to use some additional action to retrieve the attachment and then to save it to the new list.
2. Get attachments action with the ID from the trigger action will get all the attachments of the selected list item
3. The third action is to create a new item in the list b with the details you have, if you need additional list item metadata, you have to use Get Item with the ID from the trigger action.
4. You have to loop through the attachments and inside the loop you have to use
   1. Get attachment content by passing the ID and File Identifier from the loop item
   2. Add Attachment by passing the Create Item action ID of the new item and then the content from the above action.

Please try it out and let me know if you have any clarifications.