Well, perhaps 'usual mixture' is a bit of a misnomer as it does vary according to what I can find at the time. Even so the general idea remains the same, mostly inorganic, large particle size, no drainage layer.
Here's a general starting point, Lava Rock/Pumice, Turface/Haydite/D.E., Aged Pine Bark/coarse Peat. Combine the three groups in roughly equal parts and sift to remove the fines. I'm not saying you have to follow this to the letter but you did ask.
I know that you will not know where to get this stuff at first, no one ever does. There are alternative to most of the ingredients and of course you can buy either the components and/or ready made mixes online.
Have you read the thread on soils yet? If not you really should. Make sure to follow the links as that is where the 'meat' is.