I've got certain stock options as an employee incentive program, how do those compare? What is a strike price? What is an exercise price? They vested immediatel

I've got certain stock options as an employee incentive program, how do those compare? What is a strike price? What is an exercise price? They vested immediately and I can technically exercise them today does that mean anything for me? As someone that is new to this (at age 23) some non-professional guidance would be helpful. I understand that a good CPA would be much better at advising me in my situation, but I really don't have the money for that (student loans are KILLING me).