Simply go to "Spending" to view the breakdown of your spending by categories or merchants. You can select a specific category or merchant to view the list of transactions associated with the selected category/merchant.
Alternatively, you can select "View all transactions" to see a list of all the transactions. To view the detailed information of a specific transaction, simply click the transaction you want to view from the list. You will then see the Account Name that was charged, a description of the transaction, as well as the assigned category.