Making sure your transactions are entered correctly is an important step in your bookkeeping. Matching transactions is a great way to make sure that your bank balance is correct. I can provide you assistance with this.
In order to match that transaction, navigate to the Banking tab, then find the transaction in the For Review section. Click on the description to open up a menu below the row, and select Find Match. Make sure that the date range includes the date of the cheque expense. Select the transaction and then Save.
If you're still having trouble matching, make sure that the cheque expense is entered correctly, you can find it by navigating to the Expenses tab, and clicking on the transaction to open the details of the cheque. Make sure the cheque is affecting the correct bank account and the correct date.