Here is how to read the spreadsheet
The colored headings at the top are the ranges of glucose values. They are color-coded to clue you in as to meaning and pattern.
Each day is 1 row. Each column stores different data for the day.
From left to right, you enter the Date in the first column; the AMPS (morning or AM pre-shottest) in the 2nd column and the Units i.e. the dose given in the turquoise column.
Then, there are 11 columns labeled +1 through +11. If you test at +5 (5 hours after the shot), you enter the test number in the +5 column. If you test at +7 (7 hours after the shot), you enter the test number in the +7 column and so on.
Halfway across the page is the column for PMPS (evening or PM pre-shot test). To the right is another turquoise column for Units i.e. the dose given at the evening shot.
There is second set of columns labeled +1 through +11. It is good to test before bed say at +3. You enter the test number in the +3 column. It is suggested that you test before you go to bed to ensure your kitty is safe for the night.
We separate day and night numbers like that because many cats go lower at night and we want to see the pattern.
The nadir (mid-cycle or somewhere usually between +5 and +7) is the lowest glucose between shots. There is a general period when it will happen which is specific to the insulin being used and testing then helps make sure your cat doesn't go too low. Some insulins like Novolin, Caninsulin and Vetsulin nadir may be at +4.