The first time this runs it may take a while because it will download everything. After that it will only download the content that has been updated or is missing.
First thing to do is get your account cookies. The cookies should be in the Netscape format. You can get them by using a browser extension. These are the ones that I tested, but others may work as well...
* Inside your library folder a file named `.cache.json` is saved and keeps track of the files that have been downloaded. This way running the download command again pointing to the same directory will only download new or updated files.
* Use `--help` with all `hbd` commands to see available options
* Download select bundles by using the `-k` or `--keys` flag. Find these keys by going to your *Purchases* section, click on a products and there should be a `downloads?key=XXXX` in the url.