You can get any information out of a Data Master, Data Grid or Data List in order to use it for other calculations or just to display it separately using event actions.
Reading entire record's instances
To get a specific Data Master's record instance or a collection of them use one of the following data sources in the Expression Builder:
Data Master: Represents the collection of all the Data Master's instances.
Data List: Represents the collection of all the Data Master's instances currently displayed by the Data List.
Data List's row: Represents the instance displayed by the current row.
Data Grid: Represents the collection of all the Data Master's instances currently displayed by the Data Grid..
Data Grid's cell: Represents the instance displayed by the current cell.
Variable: Container of any of the mentioned data types above.
Additionally you can filter any of the data sources mentioned above in order to get a more specific record instance. To do so, you will need to create a Filter expression in the Expression Builder dialog.
Reading record instance's fields
To get a specific field from a Data Master's record instance in the Expression Builder you will have to use the Select function. The Select function needs two parameters:
First parameter: Introduce here a Data Master's record instance or a collection of instances. To do so, you can drag and drop any Data Master, Data List, Data List's row, Data Grid, Data Grid's cell or Variable containing record instances.
Second parameter: Introduce here the Data Master's field you want to get from the instances' collection.
If the first parameter defines a collection of record instances, then the select operation will return a list of values:
If the first parameter defines a single record instance, then the select operation will return a single value:
For further information check out the video tutorial: http://www.justinmind.com/tutorials/advanced-level/edit-forms/