This one is a very basic, very quick little lesson - probably relevant only for the real beginners out there, but understanding the guitar root notes for each chord you play is quite important.
In general, the root note is going to be the lowest note in your chord, in terms of pitch. Definitely this is the case in all of the open chords and bar chords. Later on, you'll get into more advanced chords, and probably see some inversions and things.... but don't worry about that for now!
The reason you need to know where the root note is, is so that you don't strum anything lower than that note! If you're constantly just strumming all six strings, your playing will sound muddy and not very precise, or even musical!
Guitar Root Notes Explained:
Video Problems? Watch Guitar Root Notes Explained on YouTube
So once you've watched this video lesson, and you understand where the guitar root notes on your chords are located, pay attention to that while you're practicing. Take the time to think about it, and make sure you're only strumming notes within each chord that are supposed to be there!