The template voyages' cargo ports can be found here:
Cargo Ports grid
All these rows are non-editable.
Read more about the grid's "base functionality" here.
Editing a Cargo Port
By clicking the -icon in the left-most column, you will be able to open up the Edit Cargo Port modal for that specific row. From the below view, you can edit the selected cargo port:
Edit Cargo Port modal from Cargo Ports grid view
Changes done in the drawer will be reflected in the rows.