WebParts

Question

I got a C# sample code from net ..regarding C# WebParts..
One thing i didn't understand that how my webparts are adding to the "Catalog zone"..  and another thing how can i show that catalog zone in the pageload itself. From the code  i got we can get that catalog zone from a dropdown list which shows all the available webparts(like Browse,Edit,Catalog,) .but i don't want that in the page load itself i want to show that .
 So here are two issues
1. how to bind my webparts to that catalog zone
2. and i need that in tha pageload itself.

thatnks in advance..
Please help me . it is very urgent for me