A table occurrence can be seen as a "virtual table." You interact with one just as though it is a distinct table. However, when you double click a table occurrence in their relationship map, you'll see that it refers to an actual table that may in fact be the same table as any number of other TO's in your graph. Thus, if you use a script or layout to modify the data through a specific TO, all other TO's that have the same data source (actual table) will receive the same changes.
TO's allow you to create multiple, different relationships between the same two tables. As each relationship matches different pairs of fields, each relationship will give you the ability to work with your data in different ways as determined by the relationship that links them. Thus, the relationship you design will determine which TO you refer to in your layouts or scripts.
You can even create two TO's for the same table and then create a relationship between them! This is called a "self join" and can be a very useful tool in many cases.
"When I establish the value lists - Do I go from the master tour table or the Tours2 Table?" If you are simply specifying that the values come from a specific field in your table, then any TO in your relationships graph that has the same data source will give you the same list of values. There is an option in your valuelist setup dialog box that lets you specify "related values". If you use this option, you can create value lists of different values for different records based on their relationship to the TO you specified. Now it can make difference which TO you refer to because they likely have different relationships.
Hope that helps you out.
Thanks again for your hel :smileyhappy: