Is there a community Q&A site similar to Stackoverflow for JIRA/Bitbucket discussions?

[Anh Vu]

I have tried to follow the JIRA online document to set up my project, users, permissions, groups, etc. but the instructions don't match with my JIRA menu. I think that even I'm an Administrator of my project, I do not have all the permissions to do everything described in the document. 

Since the default permission settings are used by over 1000+ other project in DI2E, others must have found a work around this issue but I do not know how to search/view their answers.

[Nic Brough -Adaptavist-]

And to answer

Is there a community Q&A site similar to Stackoverflow for JIRA/Bitbucket discussions?

Yes.  Here.

[Steve Thornhill]

It sounds like you've found the right things to change, so you are on your way.

A JIRA admin can set up a new permissions scheme for your project which can be customised for your needs, just having project admin rights isn't enough to perform this step, but you can change the scheme once it has been created.

You can manage which users/groups have access to your project from within the project admin screens.