Opening Balances and Profit and Loss

Hi, newbie here so please be gentle!
We have moved across from another accounting package at the end of our tax year and have manually entered opening balances for the beginning of the tax year taken from the trial balance and some transactions for the month.
Quickfiles P+L is saying that we have made a substantial profit which seems interesting as we haven’t invoiced for anything yet!
Why is the P+L taking the cash amounts in the bank accounts as income? Sure there is a simple explanation, just don’t know what it is.

Opening balances wont include P&L items from last year. It will be purely balance sheet items and any accumulated profit or loss would show in P&L reserve a/c. You dont need to enter last year’s TB just closing journals i.e balance sheet items. I just delete last year TB and enter again only BS iterms

Understood, we only entered BS items for the bank accounts as the company is quiet for that month and has no transactions either debit or credit so it’s a good time to start, still not sure why the P+L is taken the cash as income.

Any cash after your previous year end should be from either closing debtors or your own money introduced. Debtors paying you after year end should be recorded like
Dr Bank
Cr Debtors
if you are tagging money in bank it should tagged as receipt from customers and donot create new invoice