Sitting on the floor with your hands on the floor behind you, place the foam roller under one of your calves just below your knee.
Focusing on just the first few inches down from your knee, roll up and down on the roller. You can place the opposite leg on top for a little more pressure.
Make sure that, whilst moving up and down that you also adjust your body so that the roller works on the muscles of the inside and outside of your lower leg.
You are doing this for 2 reasons. Firstly you are warming the muscles up and secondly you are looking for any areas that are either particularly sore or feel restricted in any way (the more you do this the more you will understand what I mean).
When you find an area that needs some more attention, spend a little time there rocking side to side over the area so that you end up moving ACROSS the muscles.
You can also spend time flexing and extending the ankle whilst applying a maintained pressure to the target area (you won't need to roll…stay still and JUST move the foot).
When you have worked on the first few inches then move the roller up a little and work on the next few inches following the same principles as above.