Different portal page for first time user

[Coen Jeukens]

Q: How do I create a different portal index page for first time users?

I am setting up a forum about "service" for a wide audience range. For first time users I want to create a different opening portal page, a teaser page (index1.php). A page that contains more explanation about the mechanics of the site. A page that is less intimidating for a first time user. A page that invites the user to register. This page should only show a subset of the forum data, predominantly an overview of the forums grouped per category. This page should NOT contain any references to threads, except for the labels mod (to give a glimpse on the content/ topics covered inside the forums.

A user registered user will be presented a "regular" vBadvanced portal page (see index2.php) with the option to customize the page and remove/ hide redundant mods.

How to create the code for the flow displayed in the picture.

Regards
Coen