You set up PDF Merger with the Quickbase Extensions installation wizard. The wizard adds the fields PDF Merger needs to the table you choose and builds the PDF Merger Parameters formula for you.
For the setup steps, see Installation wizard: PDF Merger:
PDF Merger setup: choose the destination table and field and the files to merge, then add an application token if your app needs one.
PDF Merger finish: what the wizard creates, and the email notification you set up afterward.
For how the whole wizard works, including the shared Authorization and Application information steps, see Quickbase Extensions installation wizard overview.