1) Select all of the images you want to apply the same adjustments to.
2) Click the "Edit Image Window" Button.
3) The window will display the first image. Use the "Previous Image" and "Next Image" buttons to navigate through the images until you find the one you wish to use as your template.
4) Make the adjustments you wish to the image using the Raw, RGB, NR/ALO, and Lens tabs in DPP 3 and earlier. In DPP 4 you have additional tabs: Basic Image Adjustments (Raw), Image Detail (NR and sharpening), Tone Curves (Raw, tiff, or jpeg), Image Colors (HSL), Basic Image Settings (color space and soft proofing), Lens Correction, Crop & Rotate, Stamp (Dust removal, cloning, etc.).
5) Click Edit->"copy recipe to clipboard" (or keyboard shortcut Alt+e then o) The changes you made to each tab in step #4 will be saved in the recipe.
6) Click Edit->"paste recipe to all images" (or keyboard shortcut Alt+e then a)
A dialog box will appear asking "Apply recipe to all selected images?"
7) Click "Yes". Depending on how many images are selected, it could take a while as the recipe has to be added to each file's metadata.
With DPP 4 you also have the option of selecting which adjustments you make to an image are included in the copied/saved recipe and which are not.
You may also save a recipe as a file for future use. With the edited image displayed in the window click Edit->"save recipe in file..." (Alt+e v). From the box that appears navigate to the location you wish to save the file and name it.
You can later retrieve the recipe by Edit->"retrieve and past recipe from file..."
Once you have applied the recipe to one file you can then copy it and paste to all of the files as outlined above.
If you already have a recipe saved as a file, you can also apply it to one or more images selected in the main window that shows the thumbnails of images in the folder you have open. You can then copy the recipe to the clipboard, navigate to another folder of images, select other files you wish to apply it to and then paste it to the selected files.
The nice thing about DPP is the recipe doesn't actually change the image itself, it just adds the information to the RAW file's metatdata and applies it when you convert the file to JPEG or TIFF.