Re: New to buddypress
Here are some short answers to your questions:
1. A custom plugin is needed for this. Or you could use an auto group join plugin.
2. Could try modifying the group template in your child theme to add a forum loop.
3. Read this – https://codex.buddypress.org/how-to-guides/changing-internal-configuration-settings/
4. Requires a custom plugin. Look at the Groups API – https://codex.buddypress.org/developer-docs/group-extension-api/
5. What do you mean by this? Adding member information? If so, use BuddyPress’ xProfile setup located in the WordPress admin area.
6. You’ll have to code one yourself. There was an old plugin by Manoj Kumar that you could use as a reference point. Will need updating.
http://manojkumar.org/user-import-for-buddypress/