Heirloom, Hybrid, and GMO Seeds

[BlueLotus]

I've moved to a new place and I want to create a garden that has plants that are either perennials or self seeding annuals so that I can collect seeds and spread them. Usually, I just get the plants from a greenhouse already grown to put on a patio and never really thought about it. But now I have a backyard and space I really want to do it right for long term. So, I've been looking at seed packages and some of them say heirloom, organic, and hybrid. So I'm unsure what most of that means. Heirlooms are fine, no problem but what are organic seeds? And how do you tell on a package if the plant is self-pollinated or needs help? I've never seen any package say if the annuals self seed which is frustrating. I never knew planning a garden was so hard. I am also trying to avoid growing sterile plants, especially with the flowering plants. Is there a way to tell from a package? Are hybrids sterile or just mixed plants? What about GMO seeds? I've heard that only farmers for huge mono-crops deal with those? Does anyone know if that's true?