The core file should contain the player contract, amendments, team schedule, training calendar, match and travel plans and messages about short-notice changes. Meeting points, departures, returns, meetings, medical appointments and individual sessions should also be recorded with dates and times where relevant.
A simple three-level chronology is useful: planned time, instructed change and actual time. This shows whether a rest period was already missing in the original plan or was shortened by a later change. The reason for a change should be noted briefly as well.
The relevant evidence is not limited to club documents. Players may contribute calendars, messages, boarding records, team-app entries and pay statements. The aim is an organised timeline, not the largest possible collection of individual files.