Some better lighting would be helpful, very difficult to see things in these videos. From what I can see you have the bar too high on your back, the bar should be just under the spine of your scapula, next it looks like your thumbs are around the barbell (again hard to see due to lighting). When following the Starting Strength model you want the bar in "low bar" position which again is just UNDER the spine of your scapula and your thumbs will be OVER the bar.
Have your read Starting Strength : Basic Barbell Training? If not I HIGHLY recommend getting a copy, the information and illustrations will be very helpful in your journey to getting stronger.
My insight here was very basic as it appears as you are a beginner, more seasoned eyes will likely chime in with corrections in more detail.