Voltas are one of those steps that will either fall in easily or that you will have to think about a bit before they work - sort of like skipping. The basic movement is the same for either partner and can be done in a variety of different ways choreographically. To begin with, we will just look at the footwork.
Step side onto your side on your Left foot, stretching your knees. (Count "and")
Voltas move because of one foot crossing in front of the other. In this case we are going to say it will be the Right foot. When crossed, your knees should be bent and "inside" one another - the back of your Right knee in contact with the front of your Left. (Count 1 - or any other number count)
Repeat at will until you decide to change direction/hear a change in the music.