Using the three currents of power is most useful during Lunar work - spells, occult rituals, times when you want the magic to do what you tell it to. Solar rites tend to be a bit more about participating and building awareness and gratitude for the world, immersing yourself in its splendour - rather than making use of it for your own purposes.
When you want to contain your working within a "circle", we make a triangle like so:
(NB - I'm not sure what order the three poles are in in the triangle yet)
For more heavy-duty workings you can overlay triangles twice or even three times - or more. Generally we place the altar on the pathway between the Lunar and Solar columns. We can place the altar at one of the columns to emphasise a current. Earth/Gaian power is implied at the center of the triangle. In this triangle, we think of each point as a column. I currently mark columns with a coloured candle, with a tarot card (Moon/Sun/Star), or with their alchemical symbol. What colours ought we use? I was using black and white for Lunar and Solar, but am now unsure of this. I think either:
We represent the pathways to power a mage can tap into with the diagram of a tree, based on the Qabalistic Tree of Life. The Tree of Life is so elegant to use and a part of the occult I've always really loved; our adaptation strips out the Abrahamic imagery as standard, but is close enough that you can put it back in.
On the tree, the Solar current is the middle pillar - and the ultimate source of power is associated with Luciferian/Enlightenment/Gnosis, as well as with the Alchemist's ultimate goal of making a tincture of gold. Stellar and Lunar power form the Left and Right pillars. But this part of the system is very much a work in progress.