@moonwalker2
Ohhh. found it, I didn't get notified because it was on your message board, remember to put a '@' before the name, that way it sends a notification to the user that they have been tagged.
As for your questions, to bookmark a story you can go onto it and press 'add' in the topright corner, that way you can add them to your reading list, perhaps one called 'read later'
As for collaborative stories, I'd suggest checking out the clubs for someone to write with, the feature of having two authors in the same document is not available on wattpad, but a lot of people exchange emails and do it by using drive etc. But the dynamics of it can be debated and decided between you and the co writer. :)
I hope this helped.