On your profile you will find a series of sections. What they look like will depend on which skin the site is using, but they will generally be laid out as a series of buttons.
Each of these buttons corresponds to a module that the system has allocated to your profile. You can create items in these sections.
Only the profile owner can see all the buttons available to the profile. Any visitor to your profile will only see the buttons that have content created on it.
So if you can see the Blog
button, but have yet to write a blog post, visitors will not see that button when they visit your profile.
To create any an item for any of the sections on your profile, go to that section and click the +
button to create something.