This is a good question!
...The short answer: The first one.
Long answer: Once you are logged into the member's area, the first chunk of lessons are sorted in a step-by-step manner, meaning that when you first start, even if you are an experienced guitarist, you should start from the first lesson and continue on.
That way, you will make sure that all bases are covered and you have a strong foundation to build on.
If you are watching a video lesson and it doesn't make sense or something is referred to that you are unsure of, it would have been covered in a previous lesson. That is why this step-by-step approach is how you will gain the maximum results.
If you do like the look of some of the lessons that are lower in the list, here are the requirements you must meet in order for these lessons to make sense to you:
1. The Basics - 100% Complete
2. The Theory - Up until the video lesson titled 'What Key Are These Chords'
After that, all lower lessons will make sense and you will be able to get the most out of them.
The Workout section is where you are going to see the most progress in your physical guitar playing capabilities. You will get results fast, but you must be patient and lay the foundations first (getting the basics sorted, understanding BPM and be able to play all of the exercises).
Keep in mind that when learning guitar, there are two parts you are improving...
Your physical capabilities and your mental capabilities.
You can work on both of these separately, then bring them together multiply your progress.
I do highly suggest that you start on lesson one and continue down the list in order until the Advanced Tricks & Techniques section. Then go hard learning whatever you like the look of.
Our lesson library is constantly growing and you already have more than enough to make you into the guitar player that you have always wanted to be.
Remember that I am always here to help if you ever need any assistance through any of the lessons.
Enjoy the lessons!