Start by standing with both heels over the edge of a step. Shift your weight onto your good leg then go up onto your tip toes. Next transfer weight back onto bad/affected leg. Then slower down for a count of 4 to 5 seconds, making sure your heel goes down over the edge of the step. Return your weight back onto you good leg and repeat the process. Repeat 15 times and at least 4 sets a day. This exercise should give you some discomfort around your Achilles but should not be too painful. This can be further adapted with advice from your Physio. This video shows you working your left leg. If your right leg is affected please do the opposite.