Completing a task analysis is the process of identifying everything the learner will be able to do once they have completed the training. In other workds, it's identifying all the content that will be included in the training.
Now creating a good task analysis is not all that easy - you must document every fact, concept, and rule that will be presented in the training. Precision and thoroughness is essential. If the information does not appear in the task analysis, it won't appear in the training.
The good news is that once you have your task analysis completed, you have also completed one fourth of your objectives and also have some of your evaluation items already written.
There is a document you may find helpful as you write your tasks. This is the "Helpful Hundred" verb list.
Sample ID Document: Task Outline and Task Analysis Diagram for Help Desk Assistants