Activity (Tour Book menu > Activity, or See every money change in Activity under Money > Settings > Money setup > Who edits money) is this tour's log of who did what, newest first.
WHAT'S IN IT: advance links created and sent, deal edits, shows added or deleted, and every money change: settlements (with what changed), expenses (added, edited with the old and new amount, deleted, restored), the Cash tab (rows added or removed, carry-overs, counted corrections), per diem runs (started, sent for signatures, signed, posted to road cash, voided, deleted), pay rates and crew pay (edited, finalized), the Master Budget, reimbursements (added, approved, paid and how, back to pending), Other Income, buyouts, and every money key hand-over.
FILTERS: pick a person, or a type (Advance, Deals, Money, Schedule).
BUSY SCREENS: the budget and the crew pay grid save as you type, so ATOM shows one line per person per 10 minutes for those, not one per keystroke.
WHOSE CHANGES SHOW: everyone's on this tour, including people you invited with their own ATOM login. Older entries are still there.
WHO CAN SEE IT: the tour owner, the tour's Tour Manager or Org Admin, and ATOM support. Everyone else (crew, band, drivers, management, business managers) can't open it: that's their role, so ask your TM. Being an admin of your own ATOM account doesn't open someone else's tour log.