Hi Subhajit.
There is no contradiction between what is mentioned in the PMBOK. As processes in the PMBOK are iterative and cyclic.
in the example below, Resources calendar is created during the "Plan Human resource management", at this stage you usually don't have exact names of your team so you create a high level calendar with the needed roles and the duration needed for each role. at later stages during the "Acquire project team", you have the exact resource names and their updated calendars (available time, planned vacations, other assignments, etc.), so at this stage you will be able to create a more detailed resource calendar.
The resource calendar will then be part of your project management plan which will get updated during the project life cycle during the project monitoring and controlling and other various activities.
hope this clears the confusion.
