The main question is that without the necessary theoretical knowledge, watching the game of the pros online, you will not be able to parse the situation into its constituent moments in order to understand why certain decisions were made in specific cases. Therefore, the initial training always starts with the theory of poker, then comes the analysis of various situations and hands at the table, then watching the game pro and after you begin to understand why he played this or that hand in this way, apply the acquired skills in the game .