OK, I am assuming you have a manual and a "C" key to turn to the 6 o'clock position, right?
If you do lets start with making the F/S SUB a "Macro 1" (168). The preceding page has the instructions for changing a key assignment.
Go to the "report table" in my manual it is on page 73. You see it is a "203", Subtotal, with the control key in the "Z" position which causes a reset of the PLUs since the last time you reset it. You determine this is a month by resetting it monthly, thus the "period". Follow the "Macro" programing which includes turning the control key to "Z" as an entry, let me know when you have this programmed. By pressing the "Macro 1" key, you will get a sequence that will reset the period of PLUs. To avoid pressing this key prematurely, I would require the "Z" key to be turned first , then have the macro do the 203, Subtotal. do you follow?
The same procedure will be used to make a $5.00 tender key, "Macro 2". Hope this helps, let me know.
You have one of he best C/Rs made today, it is worth the trouble.
Now to program the "Macro 1" key you use the procedure "program a macro" on page 153.