Change your role to 'Controller' via the drop down arrow top right of your screen:
You will immediately arrive in the Controller's Dashboard with an overview of users you are controller of if there are
- Expenses for controlling
- Expenses to approve
By clicking on a users' line in the first section - Expenses for controlling - you will be able to see all of the expense you can control or reject and you can open each expense line for more details.
By clicking on a users' line in the second section - Expenses to approve - you can send a reminder to the approver so he/she does not forget to approve or reject the expenses the users submitted.