For user dimensions. If there are more than one rows for a user, how do you select the correct values? or must that consideration need to be done at the query level when set up?

If the user has multiple rows with different dimension values, they will be included in the results for each of the dimension values. So the total number of users in a dimension breakdown might be greater than the number of users in the test because some people may be double counted.

ok. so I have to make sure to get the latest and not all of them.