You mix up the mouthwash solution and use it frequently throughout the day.
You also mix up an activated solution. This solution uses acid to activate the sodium chlorite. This releases some of the available chlorine dioxide as free chlorine dioxide. This free chlorine dioxide can penetrate gum tissue and possibly get to the infected area.
To activate the solution you need to use an acid. Pick whatever acid you like. The goal is to lower the pH of the sodium chlorite to about 3. The activation takes about 10 minutes. After that you add your water and adjust the pH to about 5.5 using a small amount of baking soda.
The reason you adjust the pH up to 5.5 is to prevent acid attack on your teeth during the minute or two of swishing with it.