Totally Confused Connecting Two Tables?

 Hello everyone.
 I need some assistance here.
 I have a web form to get information about user details.
 The web form has two parts.
 the first part is user personal information  where there is few textboxes, dropdownlist , radiobuttons , checkbox etc.
 this is where user inputs his personal information.
 the second part contains the office information where there is few textboxes, dropdownlist , radiobuttons , checkbox etc too.
 but the second part is automatically populated by data from the database(lets say table1).
 this happens as soon as user selects an option from dropdownlist in second part(here an option for dropdownlist is name of the office) .
 there is also a save and cancel button at the end of the form.
now what i want here is, whenever i click a save button in my webform,
i want the data of first part of my webform (ie user personal information) to get stored in new table(say table2).
but i dont want the data of secont part of my webform(ie office information) to get stored in table2.(coz its already stored in table1.thats from where
it got populated earlier).
But i want a reference of second part of my web form(ie office info) in table2.(only the reference id of related data from table1.not the whole data)
and finally i want to display data from both the tables in one single details view.(both personal and office information)

i hope u people are gettin it?

i know i have to use foriegn keys.but i dont know how to use in this case.(sql express)

and can u plz explain how to implement this in cs file with example including source code.(c#, vwd2005 express, sql express).
 
thanks.
 
jack.