The spreadsheet can be found here and in the Important Links section in the middle column. You should be able to view the spreadsheet but not be able to update it (assuming the permissions work out properly).
The spreadsheet has two tabs: one for each group. The tabs are found on the bottom of the spreadsheet.
The coding for attendance will be as follows:
P - Present
A - Absent
L - Late (arriving)
E - Early (to leave)
Yes, an easy mnemonic to see if someone's attendance will pale in comparison to another's. Pun fully intended as the mnemonic.