Start with little or no weight. I started my squat with the bar and 2x25 pound weights. I've reached 4x45 pound weights + the bar after about a year. I took it slow and steady because I did not want to injure myself. I actually had someone compliment my squat form the other day! Thats a great feeling knowing where you started. Like anything, you just need to devote effort to getting better.
Similar for me. I started with just the bar (20kg) in April, and am now at 120kg (i.e. bar plus two 45 pound weights and one 12.5 pound weight on each side).
Just make sure you log everything, and keep pushing yourself, but with good form. Squat to (slightly below) parallel.
