Simple transactions are the ones regarding two accounts (one Debit account and one Credit account) and entered in one single row. Each transaction has its own document number.
Composed transactions with more than two accounts involved, have to be entered on several rows. The user should enter one account per row. The counterpart account for the entire transaction has to be entered on the first row.
The document number, entered on the different rows, is the same because we are dealing with one and the same transaction.
In composed transactions, the dates of the transaction rows should be the same, otherwise, when doing calculations by period, there may be differences in the accounting.