All the information on getting started is there.
I’ve googled for other states, but they seem to be far more vague than Pennsylvania (some seem to offer a generic civil service exam, which is one test and used to fill vacancies). The PA system is very comprehensive, offering different tests for a variety of different jobs.
I’m sure the need for jobs is directly related to the population. PA is a big, dense state, so that might explain it.
If you need any other help/advice/links, don’t hesitate to ask.
EDIT: It seems many states’ civil service consists entirely of job postings open to the public. This is nice, but it does absolutely no weeding out. I scored a 98 on my CT2 test and I received availability surveys/interviews pretty consistently. I got a temporary 2 month position as an Energy Assistance Clerk (which gave me direct experience). From there, landing a permanent position wasn’t hard at an interview since I’d basically already done it.