How do I figure out when to start paying?

I took out an unsubsidized loan that means I have to start paying interest now versus a subsidized loan which mean I start paying when I graduate, right or wrong? If I have to start paying the interest now when do I start making the payments? I don't want to find out that I should have started paying like months ago and I'm missing payments, but I have no idea when to start my interest payments and I know that if your late or behind on payments it lowers your credit score right? I kinda figure that if I'm behind on my loans they'll send me a notice right?