The Transaction List button is available when there are already downloaded bank transactions. Below is a sample screenshot to show you its location.
Then, the Transaction List window pop-ups similar to the screenshot above. It lists all pending bank transactions waiting to get reviewed.
If you can't see this button, click on the Download Transactions button instead. It lets you download transactions from the bank. From there, you can start categorizing them.
In case there are no bank transactions, you can download them manually. Here's a reference for you for the detailed steps to follow: Import web connect (.qbo) files.
I'm happy to help you show where the Transaction List button is. Please let us know if you've got any questions.