Measures and bar lines refer to the time that you have as the music is going by to mathematically fit a certain amount of notes in that time.
You can call one amount of space a measure. You can call it bar. What separates the end of every bit of time are these bar lines that are drawn straight down the area of music to separate the notes. The notes fit inside of this space. Mathematically, it has to fit or else there wouldn't be any sense to having any bar lines.
Bar lines are just in the music to separate everything mathematically. You don't have to stop. Some people will see them in their peripheral vision as they're reading and it will sort of interrupt their flow of notes. That's really not the case of bar lines. It's just basically, mathematically separating what is going on in this measure or bar, separated by what's going on in that measure or bar.
You'll see it as you look at music, every piece of music has bar lines. It doesn't matter what the time signature is. It doesn't matter what the instrument is. It's just a small device that separates and organizes the amount of information that's going by in a time of music.