In general you don't HAVE TO break your work to tasks and track them. Many people can hold the whole project in the head and that is completely viable strategy. However, small tasks give you a sense of progress. You experience a good sensation when you mark task as Done.

Most likely you don't need iterations. Just a list of tasks sorted by importance is OK. As mentioned, Trello is a very good choice. It is free and visualizes progress. Physical and simple Kanban Board will server as well.