Just grab the Innova DX starter set, Amazon is fine.
They are lightweight (150 gram range) easy to throw discs for absolute beginners.
When you think you have outgrown them you can start to piece together a better set with beginner discs in the 165 gram range I would say but in a more premium plastic blend. They will last longer, meaning they will typically be more stable for many, many more throws. Then from there just work your way up. It's going to take a while to learn the different molds, plastic blends, and weights you like. But it will come, just don't overwhelm yourself with too many discs just stay with a few easy to throw ones to start out.

Hope this helps.