Lesson 1 - It's not as easy as everyone would want it to be but it is most rewarding.
Now that I have that out of the way...
Not all beginners are created equal. Some need to learn the parts of the guitar. What is a fret, neck, nut, bridge. What is a note, what is a chord, what is a time signature, how do we keep a beat, a quarter note, an eighth note, a measure.
Some beginners want to add music theory to the learning some couldn't care less about theory. There are great guitar players that admit that they don't understand theory at all. When I started with guitar I knew how to play piano, so when it came to theory I found it easy to think about white and black keys, and not strings and frets.
Why am I saying all of this because everyone comes to guitar with different knowledge and experiences, combined with different goals. So lessons labeled as beginner might still be advanced for some.
First you should learn the parts of your guitar. Then you should learn the string names, its not hard, 6 strings, two of them are the same. Then you should learn how to tune your guitar. Tune your guitar every time you pick it up. Use an electronic tuner. I recommend a Korg GA-30 if you don't already have one. Listen when you tune, listen to what is flat or sharp, or "in tune". Then go through the Guitar Fundamentals 1 and 2. These are the basic bedrock courses.
Don't be concerned that they use an electric in the video. The NOTEs are the same! The note at the first fret first string is an F on an electric and on an acoustic guitar, the note at the third fret first string is a G on both guitars as well.
Work on Finger Strength. You will hear a lot about callouses and developing them. They make playing easier.
How hard do you press on a string. Hard enough to make the note ring clear. No thunks or thuds.
Come back and ask questions. Guitarists are the most giving of all communities in their knowledge and opinions and help.
This is a great site, but there are also others that you can use and visit.
Some I like are
www.GuitarForBeginnersAndBeyond.com
www.GuitarNoise.com
Remember that while this site and others have lessons for beginners they also have lessons for those beyond.. so you have to dig a bit for the lesson that is right for your level of personal development but they're not hard to find.