Mustangansta

A quote from Wiki -"The 5R55S featured the option of Ford's SelectShift, which allowed drivers to mimic shifting like a manual transmission without a clutch. The 5R55S, minus the SelectShift feature, is currently used in 2005 and later models of the Ford Mustang"

I am trying to learn how these work, the differences between single and dual clutch, padal shifts, and how they are similar or different to our 05 + auto trans.

Example: We can shift on our own but should we and how does it affect the trans if we dont have the "selectshift feature" (tci ratchet shifter)