Use the Member Selection button to open the selection dialog box.

The dimension dropdown at the top lists the dimensions on the grid. Select a dimension.

You can use the Filter  button to search for members. To filter the search to a specific level of the dimension, click the Search in Level  button. From the menu that opens, select the level.

Then, perform the search.

To return the search to all levels, select All Levels in the menu. Selecting Reset All Dimensions returns the search in all the dimensions to All Levels.

Select the members you want and click OK. The selected members will appear in the members list box.