Since ZREGION is a relation table, you need to create a new table in xtraction to reference the LOCATION LIST, make sure to map primary key and name. Also make sure to check "list, filter, groups and other wanted attributes".
You can then MAP the foreign key on REQUEST table, create a left join between request.foreign_key to location_list.primary key.
To understand, just take a look at how ASSIGNEE is mapped.
And to be honest, you should take SQL courses. You clearly don't understand how a relational database works and it will facilitate your life if you have to work with Xtraction and SDM