The link number indicates which working paper (i.e. CA = PPE1) the row is linked to. Use the popup menu to select another PPE working paper if more than one working paper is being used. This can also be linked to a map, account or group number depending on the default link selected.
You can edit existing input paragraphs or insert more paragraphs using the express menu. Refer to Input Paragraphs for more information on inserting paragraphs.