@Dragonwinter What do you mean by how? Listing them is the only way I can think of. Unless you mean something else?
If you're referring to posting, you could make a separate place for it in your works titled "[Story Name] character name pronunciations" or something like that to keep it out of your actual story chapters. You could also make a document with them or place it on a blog somewhere else that you could link to for readers who are interested. You could just place the external link next to your chapter and mention it in a short author's note at the end of the first chapter or something.
Of course, you could place it before the story chapters as well, but I would bet the readers would skim right over it if you did that, so it might end up being pointless. The only other thing I can think of is throwing a few pronunciations at the end of each chapter whenever a new character is introduced. It's all up to you. A lot of the time, readers will come up with their own pronunciation for a character name as they read and prefer their own way no matter what the real pronunciation is, so you might want to keep that in mind as well. Not to say there aren't readers who would want to know of course. XD