To open an existing Mask file: 1. In the Directories list box, double click on the directory where your Mask file is located. 2. Click on the Filter push button to list available Mask files. 3. In the Files list box, double click on the Mask file you want to open. To open a new Mask file: 1. In the Directories list box, double click on the directory where you want the Mask file to reside. 2. Click on the Selection entry box. Enter the new file name with an MXK file type. For example, TESTMASKS.MXK. 3. Click on OK.