how to use XML here?

Hi,
i am new to XML and desperately need an idea on how to proceed with the following:

i have created GUI using which an user can select a map of a country and some relevant data on that country. the user is allowed to choose one map from a list of predefined maps.
now the user's selections are to be encoded in a XML file that is to be transmitted to a Server that performs some processing. now how can i define a XML file that represents the dynamic user selection.
for eg, the user selects the map of USA from a list of maps of various countries and a data file representing the area and population of each state of USA. the XML file that i should define should indicate the user's selection of USA and the relavant data files. this XML file is then transmitted to a server. the server performs the calculation of the density of each state and returns the result back to the user.
can u help me out in defining the XML file that indicates the dynamic user selection. help with some sort of pseudo code will be appreciated
thanks in advance.

Hi,
Sounds to me look you haven't read the commonly available tutorials ;-)