GJ create menu

I found this answer about this subject:

Joomla Backend > Menus > GroupJive > Select Links (checkboxes) > Move > Select Menu > Move

You need to generate links first by doing the below.

Joomla Backend > Components > Community Builder > Plugin Management > CB GroupJive > Frontend URL (top of page below menus) > Create Menu

You can also generate menu links to specific categories or groups by doing the above same steps with small difference of editing the category or group from backend (must pre-exist for Frontend URL to generate).

But I cannot follow your step by step tutorial:
how and where do I suppose select the links (how and where generate?)
If I go to GJ menu I just see a list of item (unpublished): What do you mean by Select Links (checkboxes); should I mark one of those items?
Please give me more details. Thank you

Navigate to GJ > Menus and you can generate many internal links to GJ. You can then move them around and use them as you would any other Joomla menu link (they'll be added to the GroupJive menutype). Ensure you're using GJ 2.6.1.

Thank you for replay. Yes, I do have 2.6.1.
Then I open menu inside GJ, I selected a group, I marked Message user, then I save it... but the menu doesn't show inside the group page... how comes?

The menu links are created within Joomla Backend > Menus > GroupJive. I'm not sure where you expect it to create, but it's to generate internal Joomla menu links to GJ.

If I want to add to groups the Message user menuItem, should I go to joomla menu > GJMenu. Then I find Message Groups (related to a group) then what?
Do I select that menu? (by the way they are all unpublished; should I chance the status?)
They are just as any other joomla menu? If so, I select one, then I have to choose a MenuItem Type, which one would be the one to be shown in the group page?
I don't know if I do understand the meaning of that menus...

GJ > Menus just adds internal Joomla menu links to Menus > GroupJive. They are just normal Joomla menu links. What you do with them is entirely up to you. If you need help copying or moving them around then please review Joomlas documentation. The purpose of the menus is to have Internal Joomla menu links to GJ so they have proper and valid Itemids for module assignment, SEF usage, etc..