There are two different view modes to suit your workflow, Simple, and Advanced. You can toggle between these view modes using the toggle button in the upper left-hand corner of the Sampler panel. 

Simple

Simple mode shows just the selected Sample bank, the eight slots, their playing status, and the Sampler Master Volume and Sample Master Mute toggle.

Advanced

Advanced mode gives you access to all the controls in the Sampler and features a further options view with additional controls, which can be toggled using the options button: 

Main Advanced Sample Slot view

Advanced Sample Slot Options view