I use quart jars to mix mine, you can use whatever size container thats appropriate. I put a couple teaspoons of calcium hydroxide in each. I then fill them up with RO water - making sure to mix it up well. You do NOT need to worry about adding too much of the powder, the extra will settle on the bottom of the container after a while. I then let them sit over night. The next day you'll see three layers, a thin crusty layer on top of the water, clear water in the middle and the extra powder on the bottom. I skim off the thin layer on the top, pour the clear water into my dosing bottle making sure not to pour any of the stuff on the bottom into the doser. In general most people drip the kalwasser into their tank as slowly as practical over night, when it will have the least affect on the pH of your tank.
Skimming off the stuff on top is healthier for your tank and prevents the doser from getting clogged.
Remember to constantly check your pH, Alk, Calcium levels until you have a good feel for what works best for you.
You can reuse the sediment a few times with no loss of effectiveness. You'll know when you need to add a little more powder when the surface layer is thinning out.