If the pages weren’t created (no reason they shouldn’t have been) create them manually as you would any WP page then head back to BP settings and tell it what pages you want it to associate.
Looking under ‘Pages’ in the dashboard, I see that it created pages named Activity, Forums, Members, etc. However, clicking on the ‘view’ link takes me to an undefined URL like ‘/wordpress/activate’. I can edit the page from there; it’s blank. If I add some text, like ‘test’, it saves it, but when I click ‘view’, it takes me to the same ‘not found’ url /wordpress/activate.
If I look in the wp_posts table, I see the ‘activate’ page, with a guid of /wordpress/?page_id=9
Loading that url redirects to /wordpress/activate, which does not exist.
If I create a new page ‘New Activity’ from Plugins -> Buddypress -> Settings -> Pages, it seems to create the page, but if I click ‘view’ from there, it goes to the non-existant /wordpress/new-activity
You don’t read those pages they are simply placeholders for BP, it uses their existence in forming it’s path to the required BP page. You do not do anything with these pages, do not edit or add anything – necessarily – to the page.
All, technically, you need to is associate your pages and BP does the rest.
You might need to visit the permalinks page to flush the permalinks cache – shouldn’t really need to but doesn’t hurt – and you have definitely set permalinks to anything other than the default as BP prompts you to? BP does not work with standard permalink structure must be one of the month or day structures or custom.