The /f/ and /v/ sounds are made by putting your top teeth on your lower lip and blowing air through your teeth. The /f/ sound is a voiceless sound (with your voice turned off) and the /v/ sound is voiced (with your voice turned on). You can put your hand on your throat and make the sound /f/. You should not feel any movement in your throat. When you make the /v/ sound you should be able to feel the vibrations.