Not all plantains are created equal. Unlike bananas, who taste the same as they ripen and only vary in texture, plantains are totally different as they go from green, to yellow, to black.
At each stage, the plantain tastes different and is used for a different purpose. We'll walk you through the process. And in case you didn't know: you can't peel a plantain like a banana (and you can't eat it raw). To peel, slice off both ends, score the peel, and pry it off in sections. Now, on to the cooking.
Green plantains are just picked and not ripe at all. They are however, still edible! They're quite starchy and very firm (and hold their shape well) and are best used in savory preparations. On their own, use them in tostones or chips or as mashes in mangu or soups and stews.
Yellow plantains are just beginning to ripen and are slightly sweet. With a few black spots, they'll still be able to hold their shape well (in thick slices) and are great for savory/sweet preparations like maduros served alongside dinner.
Black plantains have reached the end of their life cycle. At this point, they won't hold their shape but they are incredibly sweet. Peel them and roast them and use them for dessert. Don't forget the ice cream.