A Forex trading plan is not very different from any other plan. It is an overview of your planned trading activity based on certain parameters you have chosen. It resembles a to-do list that needs to be completed in your trading activity.
The main idea of the trading plan is to develop a set of rules to follow and to know how to implement them. Once you have these rules written down, it is easier to apply them, as there is a clear action plan for how you manage daily trading.