How to copy list attachment into a document library with a Look Up column?

[nilonapo]

I need to copy the attachment from my custom list, into a document library that has a lookup column referencing the custom list. The linking column is the Title, so as to create a master-detail relationship.

I am new with Nintex and it will be highly appreciated if anyone could share their input how to accomplish this requirement.

[Niklas_amexus]

You can use the action *Copy to sharePoint'. Just select the document library where you want to store the document and store the new document URL in a variable. 

After that you can use the "update multiple items" action. Select the document library and set a filter to retrieve the right document (in this case the previous added document, you can use the URL Path for example). Then update the Lookup column with the id of the current item for example.

Hope this works for you!