If I get it right, you are making SQL insert, you get back id and based on that id you want to insert other rows into another table?
just use SqlCommand to insert data.
if you have a lot of data you should think about batch operations.
you can also use SqlAdapter to synchronize data with your database.
if you want to know more about this topic
try for example this:
Using ADO.NET for beginners[
^]
or just google ADO.NET or c# SQL or somethink like this. If you have more specific question, just ask I will try to help :)