The stav is a volvas most important tool, aside from herself. The stav is a vertical line, because that is the literal translation from Norwegian-English of the world itself. It is often in the form of a wooden staff, though there is no set-in-stone way for making a stav (older ones, traditionally, have been found in the volvas graves to be made of iron as well). It serves a variety of purposes. For one, it is a symbolic instrument. The vertical line represents a living person, and a horizontal line represents a sleeping/dead person. The way the stav is made is to represent the World Tree, Yggdrasil, and through this connection it aligns the volva with the energy involved therein and allows her to do her work. The stav is aligned with the spine of the volva using it,becoming a symbolic representation of her. It is used to channel energy, just as Yggdrasil does, and through it comes the power of most of the volvas workings. (It is not unlike how a stang is used).
How the stav is made really depends on the volva or seidhr-worker. Generally it originates from a wooden stick. The type of wood you want to use for this varies and depends on the person. Most like to choose something that has significant or personal meaning to them in order to connect them better to the stav itself. However, it can come from a tree in your garden, a random stick you happen to find, a broom, and even (I've seen this seriously suggested from a profession) a wooden spoon. The width and circumfrence and height and so on do not really matter in how the stav functions. HAVING SAID THAT: It will depend on what kind of techniques you plan to do. If you are sitting, ideally, you don't want a stav to be too giant and looming over you- the length appropriate for this would be to your shoulder. If you're standing, the height matters a little less- you simply want it tall enough so that it aligns with your spine and keeps you straight.Weight does come into play. You want to be able to lift and move the stav, so don't choose something you can't carry. The stav is decorated different from individual to individual. It's much like a stang, in that people often tie colorful cloth and ribbon to it, add stones to it, and smear their blood on it to make it very personal.
So to use the stav itself, you need to get comfortable with different movements and techniques that incorporate the stav before you get started in deep workings. It's improtant that the stav eventually feels like another piece of you, like an extension of your arm and your self, so that the movements do not interfere with your seidhr working but rather combine with it to boost you along. The first thing you'll want to do is put down the stav, and simply stretch. Yoga is a good way to get warmed up. Runic Yoga? Even better. You should stretch and pull till all of your muscles feel loose and warm. Stretch and bend until you are limber and ready for work. You should also do this AFTER you've done a seidhr session with the stav.
If you're unfamiliar with using a stav, start by sitting. You want to be very straight in your posture, holding the stav directly in front of the shoulder of whichever hand you're using to grasp it. Align yourself with it, so that you resemble the stav. Your legs should be crossed, and out of the way- but your feet should still touch the floor. If you want to start by standing, feel free to do so- you should make sure your feet are evenly apart (ideally shoulder width). Your shoulders should be aligned with the stav out in front of you, and your arms should feel loose and capable of moving.
The proper way to hold the stav is between your pointer finger and thumb. Don't grip it too tightly. It should just be held onto enough so that it is stable and still, without taking any energy or thought.Sit like this till you feel you have a stable grasp on it. And then incorporate the rhythm. Gently and slowly lift the stav just barely off the ground, then let it go and allow it to "bounce" back up to where it was. Find a rhythm you like, which helps you along, and stick with this. Focus on the rhythm, the sound of the wood, the vibration moving through your hand. (If you are more experienced, you will use a tein as well. This is a short stick which resembles a wand, and it is used by the less dominant hand to lightly hit the stav and add another layer of rhythm to the beat. I'll go into it later). As the rhythm steadies, and you become accustomed to the feeling, you want to match your breathing up to the same rhythm. Breathe in for each count and out for each count, until it becomes an unconscious thing. And once that occurs, you incorporate the rest of your body into the movement. Generally, the volva or seidhr worker appears to be "swaying" or "seething", their body begins to rock back and forth in the same time as the stav, mimicking it. This is what we refer to when we say a volva is "riding" the Tree. If you are standing, imagine roots where your feet are, holding you to the Earth as the rest of your body ripples and sways.
To incorporate galdr, as you breathe out- sigh the name of a rune. As you breathe in, try to do the same. Eventually, you should be sort of softly chanting the names of runes as you breathe, which should be in time with the rhythm of the stav beat and the movements of the rest of your body. From here is where inspiration normally hits, and the volva begins to sing of her own accord- generally a song incorporating the runes, which holds personal meaning to the volva and helps her to get into a steady trance. This uses two different techniques for altered states of consciousness, the path of breath and the path of rhythm. This is the basic concept and idea for this working, and how to get into it. I'll probably share a bit from a book on aligning with the tree, and how visualizing can play a critical helpful role later on.