Use your own account. Your name and signature go on every report you save.
The full name is printed under the signature on the reports, so type it exactly as it should appear. The signature picture is stored in the SIGNATURES folder under that name.
These two Excel files are shared by every branch. A manager downloads one, edits it in Excel, then uploads it again. The form uses the new version straight away (press refresh after).
Each branch has its own Excel file. This computer remembers your choice, so you only do this once.
Normally found by itself: it is the RECEPTION file in the same Dropbox folder as this branch's records.