Seed for Birds

I inherited a bird from my grandmother and I don’t know what to feed it. I’ve never owned a bird in my life. I just recently learned it was a finch. But what do I feed a finch? I’m smart enough to know I can’t feed it human food (duh) but past that fact, I’m lost. Is there a specific type of bird food I need to get? I’ve been searching around for details and there are a number of sites that talk about bird seed, but which site is the best? Actually, I don’t care about the websites. I just need to know what seed to get this bird.