A judgment is enforced by choosing a method that matches what the judgment debtor actually has. A warrant or writ of control takes goods; an attachment of earnings takes wages; a third-party debt order takes money held by a bank or trade debtor; a charging order secures the debt against property. An order to attend court for questioning (N39) is the route where you do not yet know which of those applies.
The practical sequence is therefore: confirm where the debtor is, establish what they have, then select the method. Skipping the first two steps is what produces nil returns and repeated fees — most failed enforcement is an information problem rather than a legal one.