Double-click on the package and follow the instructions.
The Aperture plug-ins are installed in /Library/Application Support/Aperture/
To export using the BorderFX plug-in choose File > Export > BorderFX, or Right-click to show the pop-up menu, and choose Export > BorderFX
To use the BorderFX Edit plug-in choose Images > Edit With > BorderFX, or Right-click > Edit With > BorderFX

BorderFX Edit plugin seems to work best when Aperture is in Browser mode when BorderFX is started.

Sharpening can improved the sharpness after the image is scaled down for exporting.
Edge Sharpening increases the contrast of the edges between pixels of different colors in an image.
Note: Sharpening is only applied to the scaled image, and is applied before the borders and text are added.
To add a Copyright Notice, add a metadata text box, and select Copyright Notice from the IPTC Field pop-up menu. If the IPTC Copyright Notice field for the image is set, then that is used, otherwise the default copyright notice is used. So set the default copyright notice, type the text you want in the Text field, it will be saved as the default. Note: Option-G can be used to add the copyright symbol '©'.
Select Save text in Preset to save the text as well as the attributes in presets, this will allow the same text to be placed on multiple images. If this option is not selected, then only the attributes will be saved, and you will be prompted for text for each new image, allowing specific text on each image, but with the same attributes, like font, placement and color.
The text boxes can now be placed anywhere on the image.
Select the text or metadata box you want to remove, then press Delete.
Either double click on the Date text in the photo, or click the icon next to the IPTC Field in the inspector.