There are a lot of things you can use this for. I just spray it on my face after cleansing and before moisturizing but you can spray it on a cotton pad and wipe your face with it and even spray your pillows with it to keep them clean (makeup and face products can build up on your pillows and cause you to break out) and smell fresh.
You can absolutely just spray it on your face to give you're skin a refreshing wake up, however I use it after I cleanse my face to restore the pH balance because the cleanser has stripped your skin of it's natural oils. After I finish washing my face with any cleanser, I spray a few times on a cotton pad and then gently wipe it all over my face. I then follow up with a moisturizer and blend that into my skin to receive a smooth gentle finish.
There are many ways to use it. My personal favorite is to just spray it directly onto my face. I'll cleanse my face, spray this on and then pat it in (softly) using my fingers. I'll then follow with a light moisturizer once the toner has soaked in.