The build command is used to render your book:

mdbook build

It will try to parse your SUMMARY.md file to understand the structure of your book and fetch the corresponding files.

The rendered output will maintain the same directory structure as the source for convenience. Large books will therefore remain structured when rendered.

Like init, the build command can take a directory as argument to use instead of the current working directory.

mdbook build path/to/book

When you use the --open (-o) option, mdbook will open the rendered book in your default web browser after building it.

The --dest-dir (-d) option allows you to change the output directory for your book.

note: make sure to run the build command in the root directory and not in the source directory