Complex sentence: The program was made from segments and sketches taken from the first 20 years of "The Tonight Show starring Johnny Carson" (1962-1982), which originally aired on the NBC Television Network from 1962-1992.
Split into simpler sentences: The program was made from segments and sketches taken from the first 20 years of "The Tonight Show starring Johnny Carson" (1962-1982). Carson's full tenure on the program, which originally aired on the NBC Television Network was from 1962-1992.