From any screen, tap the magnifier in the top bar or press Ctrl+K (⌘K on a Mac) and start typing.
Arrow keys move, Enter opens, Esc closes. A guest opens their record; a booking opens its card on the Reservations screen with the calendar on that day — refunds and notes work from there even for a booking months back.
It's deliberately just people and bookings. Settings and help live in the left menu.