The highlighted yellow numbers are the period numbers, and the ones in parentheses are day numbers.
The way to read the schedules column is: On an unrotated schedule, for section Phys Ed 6 Sem 1 (08603-005), it is period 4 on days 1, 3, and 5. On a rotated schedule, it is period 2 on day 6, period 4 on day 1, and period 6 on day 3.