Beginning Balance transactions transfer remaining balances from your Legacy system to R365 and are mostly entered during the implementation process.
The only time(s) when an additional Beginning Balance transaction would need to be entered is if an invoice was received or payment was made after the initial Beginning Balance entry. You would then need to delete the original entry and enter a new Beginning Balance, which should be dated prior to your Go-Live Date.
Ensure that you are not using Beginning Balance transactions for your regular transactions (AP Invoice, AP Credit Memo, Journal Entry, Stock Count, ect.), which should be created via their respective menus listed in the top ribbon.