Manga are Japanese comics or graphic novels. They're usually printed in black-and-white, and also typically read right-to-left instead of left-to-right. Chapters in manga are similar to issues in American comics, and are collected in tankōbon volumes which are similar to trade paperbacks for American comics. Unlike American comics, chapters are often released in manga anthology magazines rather than as individual issues.
Manga World - A video on the history of manga and the culture surrounding it.
Manga (漫画) - Japanese comics
Manga-ka (漫画家) - Japanese comic artist/writer
Tankōbon (単行本) - a book collecting a single volume containing several chapters of a manga.
Doujinshi (同人誌) - Similar to a zine, self-published Japanese magazines, often based on other popular works (including manga).
Manga zasshi (漫画雑誌) - Manga anthology magazines like Shonen Jump.
Most manga reads right-to-left just like the original versions published in Japan, however some mangas are flipped when published in English. Usually the book will indicate whether it is flipped or not. Here is a diagram illustrating how to read panels in a traditionally formatted manga.
Source: https://www.wikihow.com/Read-Manga