gathered that theyre about seniority of associates at law firms but could someone expand upon thrm ie how many years does it take, just general information. Thanks.

For T1s, you move up a level with each passing year (unless you show unusual levels of incompetence):

Straight out of law school: A0

+1 year experience: A1

+1 year experience: A2

+1 year experience: A3

+1 year experience: SA1 (unless you're at AZB, they give SA at 5 years)

So on and so forth

After SA, it varies basis performance, the firm and (sometimes) your luck. A good thumb rule is SA for 2-3 years (and 4 at AZB).