The short answer to why you need to plan your information task is to save time. When we feel enthusiastic about a new project or activity, the temptation is always to leap in immediately and rush around doing things which may not be the most useful activities in respect of the project as a whole. Rushing on like this means that we may miss out crucial activities, undertake activities in the wrong order so that earlier ones must be repeated or fail to schedule enough time to complete all the activities. Proper planning avoids these pitfalls.
You will be asked to produce an action plan for your information task. This will list the activities which you plan to undertake and the resources which you will require and put them into a realistic timeframe. In order to produce this action plan you will find it helpful to think systematically about the planning process.