Generally, the Filter and Grism wheels have default elements and are unchanged run to run. If the observer wants to change an element in these wheels it is done through the Green Sheet sign up or by contacting instrument support directly.
The Aperture wheel is usually populated by the visiting observer. Some instruction on this process is in this manual and more info is available on the mountain. Of course it is best to have instrument support, or the daycrew, show you how to insert the apertures. The names on the wheel gui menus are changed by hitting the stop button at the top of the wheels gui vi. Next right click on the pull down menu for that wheel and select "properties". In the pop-up window that appears, select "edit items" to change the aperture wheel names.