1. Open Apple Aperture
2. Select an image
3. Right click (control-click) on the image
4. The contextual menu will appear, select Edit With
5. Select PhotoTune
6. The PhotoTune for Aperture dialog will appear, select a preset from the list and press Apply.

For Details on using the PhotoTune for Aperture dialog look below.

Note: Aperture only supports editing one image at a time. You may only select one image at a time for editing.

• Search: Type in the name of a preset. The results will appear in the Search Results category. 
• Category List: Lists your preset categories. Click on the triangle to open each category, just like the Preset pane in PhotoTune.
• Description: Displays the description for the selected preset. You can close this section by clicking on the triangle next to the section title.
• Cancel: Cancels PhotoTune for Lightroom
• Open...: Rather than applying a preset directly, this option will open your image in PhotoTune so you can manually select the options.
• Apply Preset: Applies the selected preset to your image(s)

Note: Aperture will always create a copy of your image for editing. You can control the file type and options that it creates in the Aperture preferences.