NOTAMs are expected to be issued 3-6 months prior to the event commencing. These NOTAMs will likely outline airspace closures and aircraft parking restrictions.
The landing permit number needs to be placed in the remarks section 18 of the ICAO portion of the flight plan.
Note that the flight plan needs to be filed a minimum of 3 hours prior to departure. Additionally, a flight plan cancellation is needed for earlier departures. An updated flight plan should only be filed after a rejection of the original flight plan has been received by authorities. It’s important to keep your trip support provider and/or ground handler updated for any potential schedule changes for flight planning purposes; these may cause delays for your departure due to increased traffic.