Do you have the other r.a.d.controls in your VS toolbox? Actually we're adding all r.a.d.controls to the toolbox and you should be able to see the TrackBar control as well.
If it doesn't appear in your toolbox you can right-click on the toolbox, select choose items, then go to the folder when you've installed r.a.d.controls for WinForms and select Telerik.WinControls.UI.dll.
e.g.C:\Program Files\telerik\r.a.d.controls for WinForms\bin
Then you can drag & drop the TrackBar control to your form and customize its properties. You can also take a look at the TrackBar example in our QSF under the following category: r.a.d.uielements -> TrackBar.
I hope this helps.