Welcome!
Don't worry about understanding all of it right now. There's a lot to understand, and sometimes that only comes with time and not getting things right.
A couple of notes:
- It looks like you started your deadlift too light, as it's too close to your squat weight, even at this early stage. Consider a few sessions of adding more than 5kg, but no more than 10kg, while continuing to add 2.5kg to your squat.
- Your numbers aren't adding up. Meaning that if you're increasing 5kg comfortably each time you deadlift and you've had 11 sessions (6 A's/5 B's) during Phase I, you should be at 110kg now. That's closer to where you should be, with a greater separation between your deadlift and squat weights.
- Stalling/failing on your Overhead and Bench Presses this early, at this load, is a couple of things. 1). You're quite light in your bodyweight, which you are working on; gaining more will help; 2) Form - both lifts are very sensitive to form issues, especially letting the bar travel outside the "groove", which means that you've lost the leverage advantages of proper form and the lever arm between the bar and the correct position are too much for you to overcome; be slow and methodical during your warmup reps, as each of those reps is practice for the work reps. Perfect practice makes for completed work reps; 3) read and answer The First Three Questions, specifically Question 1.
re: your Squat video:
- Make sure you set up the camera exactly as described in the Technique forum. Basically, the same angle a coach would be seeing if they were standing there in person. It will make things easier for everyone.
- From this angle, you're right, you aren't low enough (3 and 4 were good depth). That's due to a combination of things - 1) take a wider stance; you stepped back with your feet at a normal standing position stance, which is just inside the shoulders. Your heels need to be at or just outside the shoulders; 2) toes angled out more, near 30° (it's not visible here, but apparent based on how you stepped out); 3) break at both your hips and your knees at the same time (you'll notice on several of the reps that you start bending over at the waist before your knees); 3) after both your hips and knees break, reach back with your hips towards the opposite wall; that will help lock your knees in the proper position and prevent the dreaded knee slide; 4) Focus on getting your stomach between your thighs at the bottom; that will ensure that you get proper depth; 5) You're driving up with your hips well on reps 3 and 4, but everything else is out of position and loose, so it's the drive alone that got you those reps; 6) If you can, find a squat rack that doesn't have a mirror facing you. Your eye position is very good as you descend, but you immediately lift your head to watch in the mirror, leading with your head and then your chest, which makes the squat much more difficult than it need be; keep your gaze down at the ground at a point a meter or so in front of you; 7) all of these things lead to a wild, meandering bar path when you want it to be pretty much straight up and down over your mid-foot; watch the far bar end in relation to the vertical paneling on the wall and you'll see it making all kinds of loops and arcs when you want it to be solidly in the groove right above your mid-foot.
- Just like I mentioned with the presses, your warmup reps are your perfect practice reps. As you've found with those presses, getting the bar outside the groove will lead to a failed rep. That's also true with the squat and will quickly become evident as the weights get heavier. Better to fix it now.
Keep at it!