Welcome to the Community, @christina74. When you first connect your banks and credit cards, QuickBooks Self-Employed (QBSE) downloads transactions from the past 30 to 90 days. Each time you sign in, QuickBooks automatically downloads new transactions from your connected accounts.
If those transactions have downloaded successfully into QuickBooks but you can't see them, check the Transactions page for a default date filter. It's possible that a default date filter on the page is hiding them. I recommend changing the date filter to Custom date and setting your desired Start and End dates.