Please open an issue here if you encounter a specific bug with this API client library or if something is documented here https://shopify.dev/docs/apps but is missing from this package.
General questions about the Shopify API and usage of this package (not necessarily a bug) should be posted on the Shopify forums.
When in doubt, post on the forum first. You'll likely have your questions answered more quickly if you post there; more people monitor the forum than Github.