For your first question I am assuming you are asking about the blog and not the bulletin module at the top.
To display more stories go to your menu manager, choose your menu (I believe your top menu is magazine) then choose the menu Home. In the parameters you should be able to set additional stories to be shown. For instance you could set 1 leading and 8 intro which would display 9 stories total.
For the tabs question, someone correct me if I am wrong here… if the tabs module is in User 6 for instance, you would set the latest news to also display in User 6 and I believe it will automatically display in the tabs. I am using a different template with the tabs module.
If that doesn’t work, go to your Module Manager and open the JA Tabs module to specify what category IDs you want displayed.
Of course, if all else fails, you can follow the directions that are given here: http://www.joomlart.com/forums/topic/ja-sanidine-userguide/ which would be my best suggestion to you.
Good Luck! 🙂