§1. To pursue an appeal it is required and suffices that a party calls upon the services of a higher judge for an emendation of the challenged sentence, attaches a copy of this sentence, and indicates the reasons for the appeal.
§2. If a party cannot obtain a copy of the challenged sentence from the tribunal from which appeal is made within the useful time, the time limits do not run in the meantime; the impediment must be made known to the appellate judge who is to bind the judge from whom appeal is made by a precept to fulfill that judge’s duty as soon as possible.
§3. Meanwhile the judge from whom appeal is made must transmit the acts to the appellate judge according to the norm of can. 1474.
Source: Code of Canon Law (Vatican.va)