I have a bookkeeping question that is driving me nuts!!!!!?

Ok, I am balancing a daysheet or record of charges and receipts like in a doctor's office. I have filled out all the ledgers and recorded all of my payments and charges on the end of the day, daysheet. Everything is balanced correctly I believe. I am down to the proof of posting and did that. I also did the accounts receivable control. My question is: on the accounts recievable proof I need to know how to find the number for accts rec 1st of the month. I can't for the life of me figure out how to find that figure. This is what my book is telling me to do. In the Accounts Receivable Proof section, enter other figures from the Month to Date column boxes. What columns are they talking about? It goes on to say...then, add, subtract, subtotal and total. If posted amounts are all correct the total accts receivable figures in the a/r Control and a/r Proof boxes will match indicating that the daily journal (daysheet) is balanced. I don't know how to get the first number in the accounts rec. Proof box which asks for accts rec 1st of month. Help asap...please. easy 10 pts for quickest correct response.