Hi link611 and welcome to Tikiwiki community
I would say that you could first try (adn learn) how tiki works step by step.
Can I suggest that you disable categories and see if your registered users can see those objects? (I guess not. Am I wrong?)
So first, read Documentation about the permission system (global perms, local perms, category perms). And play making changes step by step.
Ask again if in doubt, after you did the previous steps, providing more information about which global group perms that you have granted, and which local perms are there in your objects, and which perms are there in your categories.