Starting Strength: Basic Barbell Training, 3rd edition
As opposed to the $23 for Starting Strength ?
> if I go even further down my back collapses even more....what do I do to fix that?
As u/BR33ZY, you need to deload your squat weight and fix your form while re-progressing.
> Also should I sit back and squat or is it more of a straight down motion? This is the biggest thing confusing me right now.
We're talking about the low bar squat here. It's different from the high bar squat in many aspects.
The idea is to push your hips back and descend untill you hit depth, then push your hips up.
For this it's better to watch and read than to just read.
This video is very good and illustrative of how to perform the low bar squat
A longer video but also very good aswell
An even longer video, also a very good one!
Read this whole section, it's very thorough!
I recommend you also read the Starting Strength 3rd edition by Mark Rippetoe .
I can imagine what you look like, given most office workers. Your posture is terrible and your weakness is posterior chain (just like most everyone else). Given that starting point....
Also, would be better to know your goal. What is your goal, your point B?
Get the book Simple and Sinister by Pavel. https://toptalkedbooks.com/amzn/B00GF2HP9G Kettlebells, two exercises, could even do at home. Fantastic starting point, work the posterior chain and shoulder strength. If you need better instruction, take an RKC class (probably 1/2 day) on how do a good swing (which most people suck at, and a good TGU. also check out /r/kettlebell
Get the book Starting Strength by Mark Rippetoe. https://toptalkedbooks.com/amzn/0982522738 It's got great descriptions of exactly how to do the big 4 exercises. I'm not convinced the program is really great for older, slower people, it's built more for 18 year olds. That said, it's still worth the investment. You might actually be too weak to get some of just the bars off and need to start with dumbbells and/or other regressions. (goblet squat instead of bar squat, etc)
This option is hit or miss. Could be great, could be a disaster. Find a good personal trainer. Have them show you how to do the basics. Bench, deadlift, overhead press, squat, row (DB and BB). I would take some time and really evaluate the trainers around you. From what I see, most are freaking terrible. (like 8 in 10 or worse). But that one, that one guy/girl can be an amazing asset. Just like yoga, you need some feedback on what you can't see or feel. I would not pay to have someone show me how to use machines. Once I get the DB/BB/KB version down, then the machines pretty much fall into place. And DB/BB/KB is always available and comparable no matter where you go.
PS. Everyone starts being able to barely move a bar. Nobody starts out lifting 300lbs, doesn't work that way. About time and effort. There's always someone stronger than you and there is always someone weaker than you.
Little late here... but the lack of stability you were experiencing is exactly why squats are considered such an important exercise. Free weight, compound exercises are just plain better at developing functional strength than machine exercises because they involve more muscles in stabilization and allow for a more natural range of motion. That's not to say that the leg press is bad, it certainly has its uses as an accessory exercise but you're doing yourself a bit of a disservice not trying to nail your squat form. Your knees and balance shouldn't be a problem once you've got the basics down (and, honestly, the leg press is probably marginally worse for overall knee health).
I'd make a go at learning to low bar squat, there's a lot of good resources out there for it. Anything Starting Strength related (like this video ) is a great place to start for technique even if you're not necessarily keen to do that particular program (most people would recommend something similar to it, though). The folks over on /r/startingstrength are usually happy to do form checks and are a very knowledgeable, respectful, and helpful bunch (granted, they'll also probably encourage you to do the program :P).
Starting Strength, buy the book. It's all you'll ever need. http://toptalkedbooks.com/amzn/0982522738
Build a solid strength base, then you'll have a much better base for other physical activites
1) Doing deadlifts. This is a strength-training exercise: https://www.amazon.com/dp/0982522738/
Edit 2: More about chiropractors: Few are MDs; the ones I've worked with all went through a 4-year, post-bachelors program. In my experience, chiropractors fit on a spectrum, going from ambulance-chasing quacks to gifted, remarkably effective healers. You want the latter. Only way to find out is to pay for about 3 visits; if you and your body are consistently feeling better physically and emotionally by then, you've found a good one. If not, stop, and go find another. So far, the best I've found lean towards alternative medicine (which was really surprising at first... I'm trained as a physicist, and was REALLY skeptical.) Can't say that's a general rule though. Again, all this is my experience; better to get your own experience and evaluate based on that, instead of blindly deciding based on something you read online.
It essentially focuses on just the squat, deadlift, press, bench press, and (later) power clean, devoting around forty pages to each, and explains why you really don't need much else. They're quite difficult to get right, but the incredibly in-depth explanations will especially appeal to programmers who like understanding how things work.
I say this just because the book completely changed the way I approach the gym, and it mirrors what the article author says about the exercises he used.
From the gloss for Practical Programming for Strength Training : "Exercise is physical activity for its own sake, a workout done for the effect it produces today, during the workout or right after you're through. Training is physical activity done with a longer-term goal in mind, the constituent workouts of which are specifically designed to produce that goal."
He emphasizes that a realistic means of progression is one of the most important aspects of any training program.
Practical Programming and Starting Strength  (which is a better introduction to these ideas for novices) are together the best analytical discussion of physical training that I've seen.
Read this . There are pdfs of the second link available out there. Aside from that, just make sure you plan things out, both your routine and your diet, and make sure you track your progress.