I have linked my bank accounts, but I do not see the transactions in the statistics. How come?

To include the transaction in your statistics, you must assign it to a category.
Just open the transaction, select the right category and then save it.

You can also change the description or the counterparty name if you are not satisfied with what the bank has entered there.

It is even possible to change the value date if you prefer to include the transaction in another month in your statistics.