We would like to start off with a few links and some basic information from the official website of the sport’s governing body, the International Skating Union.
Here is the Handbook for Technical Panels. The technical panel is responsible for assigning levels to each of the elements, which includes evaluating the key points for the pattern dances.
Here is the Handbook for Referees and Judges. The Judges are responsible for assigning Grades of Execution (GOEs) along with a Program Component Score (PCS).
Here is the Handbook for Officials on Pattern Dances which includes descriptions of the various turns you will see in pattern dances as well as further information on GOEs.
"The Technical Panel is composed of the Technical Controller, the Technical Specialist and the Assistant Technical Specialist, each one from different ISU Members (countries). A Data Operator assists them for recording purposes. An instantaneous slow-motion video replay system operated by a Replay Operator supports the Technical Panel in the identification of the performed elements. All final decisions made on elements and levels will be made from the majority opinion of the first three technical positions."
TECHNICAL SPECIALIST (CALLER) - "The Technical Specialist, assisted by the Assistant Technical Specialist, identifies and calls the performed elements and the specific Levels of Difficulty of certain performed elements (e.g. Spins, Footwork,). He/She identifies illegal or additional elements, identifies falls and adds, if applicable, innovative elements."
TECHNICAL CONTROLLER- "The Technical Controller authorizes or corrects all calls, supervises the Data Operator and can propose corrections, if necessary."