When you now start up STK, you will need to add the Orbit Tuner to your STK work space by right-clicking anywhere in the top Toolbar area and choosing to activate the Orbit Tuner UIPlugin Toolbar. Now you will see a new Orbit Tuner icon. With a scenario open, click on the Orbit Tuner icon which will open the Orbit Tuner panel, shown below.
The Orbit Tuner UI plugin allows you to use slider bars to change the value of the orbital elements and have the orbit updated in real-time in the 3D Graphics Window. you can also type in values to change the orbit.
You can also use the "Show" check boxes to see the Classical orbital elements in the 3D Graphics Window. The check boxes next to the elements are used to toggle the vectors and angles on and off.