To Create a Configuration Variable Link

In the Links tab of the Explorer dialog, click the Create Link icon and from the drop-down list, select Configuration Variable Link.

The Configuration Variable Link dialog opens.
Do one of the following:

Select a predefined expression from the Sample Types drop-down list.

or
Select New from the Sample Types drop-down list to create a new expression.

For a predefined expression, the definition of the selected variable appears in the Sample Types drop-down list and the resource filter displays in the Object Filter.
(Optional) For new expression, do one or more of the following:
1. Select the configuration variable from the Scope drop-down list.
  You may create a custom configuration variable and define it with the desired folder path to harvest. For custom configuration variables, make sure you add "\" at the end of the directory path.
2. Enter the file type in the File Type field.
  You may select the desired file type from the drop-down list or enter other file types such as docx and xlsx. Multiple file types can be separated by semi-colon.
3. Select the resource filter from the Object Filter drop-down list. For harvesting non-dgn files, select No Filter in the Object Filter.
Click OK.