You should have watched all the original series first.
MotoDork
2025-08-06 14:30:14 +0000 UTC
The bars on the sleeves of the Starfleet tunics are braidless sleeves, which indicates each character's military rank. They more or less serve the same purpose as the circular pips crew members wear on their collars in the spin-offs (TNG, DS9, Voyager).