For your benefit, below are training videos that will demonstrate each of the altar server duties and at what part of the Mass you will be expected to perform the duties. You are expected to know how to perform all duties if called upon.
Exceptions include 5th and 6th grade servers and new altar servers that have not yet received and demonstrated proficiency in all duties. They will have limited duties throughout the first year of altar serving. Additional training is required for the duties of crucifer (cross bearer) and candle bearers.