Most likely the first thing you noticed in this entry is the diagram. Great if you're a guitar player. But what if you're not? After all, the title of this lesson didn't mention anything about guitar or bar chords. We did that on purpose. Read on...
This lesson is not an overly complicated one. It's two versions of a B7 barre chord played at the 7th fret on your guitar. The first version uses all four fingers of your fretting hand. The second version does not use the pinky finger. Play both versions and listen to the difference in sound. Observe the difference in feel. You might now wonder which chord version to use? They're basically interchangeable. This can depend on anything from the mood you are in to which other musicians you are playing with. What sound are you after?
For non guitar players a third version is given that shows the notes of this chord. Guitar players can learn these notes to. Notice the bracketed F sharp note. That's the note you get when you lift your pinky finger off as in version two of this chord. As a non guitar player you can create your own versions of B7 based on these notes.
As a guitar player you'll realise that these are movable chord shapes. Move the shape up and down the guitar neck to create new chords. Try both versions and see which suits whatever you are playing at the time.