How to populate form from CB fields?

Hello,

i have some trouble setting up a feature for a new homepage, so hopefully some of you guys can help me out.

It is about a car-workshop where members can make online service appointments. I use CB to setup the whole Community-Features like PM, Forum and user profiles. Within the user profile i created one Tab called "My Car", where members can add all the information about their vehicle(Brand, Engine...).

Now when a member is using the form for a service appointment, i want to show all the information about their car inside that form.

Since i only know little to nothing about PHP/SQL, i am pretty lost here. I know that i can get the information with an SQL query but i have no clue in which database table the data is stored.

Hi,

i found a tutorial for exactly my case.

Obtaining field values

But where do i have to put the first code to establish the $user? If i put the code into my index.php my site stops working.