You don't. You save your images in srgb. You use the profile to soft proof your images to see what they'll look like when they are printed.
Actually, that's not correct.
You can use the profile to soft proof your images while editing them (which should be done in a conventional color space such as Adobe RGB or sRGB). Once the image editing is completed, you "Convert to Profile", taking the image from the editing space and converting it to the printer profile. You then save it as a JPG or TIF file and send it straight to the printer at Costco. Don't bother tagging the image or embedding the profile, since the Frontier/Noritsu printers don't read the embedded profile or color space tag.
For full instructions see: