Keep the written offer, any correspondence describing pre-travel activities, meeting invitations showing location, and payroll records showing when payment began. These make it possible to describe the sequence accurately later rather than reconstructing it from memory.
Create the record while the details are fresh
A simple dated log of what was attended, from where, and whether it was paid takes minutes to maintain and is difficult to rebuild months afterwards. Store it with the employer letter and the offer. If questions ever arise about when employment began, an accurate contemporaneous record is more useful than a later explanation, and it also lets counsel answer specifically and quickly.
A transcript showing a degree completed in two years invites a question about the years before it. Separate records that show preparation for the role from records that would show professional duties already being performed before admission. Equipment shipments, account provisioning, and a training schedule usually follow the employer's own internal timeline and do not by themselves indicate paid work, so keep a dated note on what each item actually involved rather than leaving the distinction implicit. A start date on a payroll record that appears to precede the crossing invites a question the employer's letter alone cannot resolve. Ask whether any onboarding step assumed availability before travel was complete, and adjust the plan itself rather than the paperwork describing it. Keep the confirmation of each date in writing instead of relying on memory once time has passed.