The third and most important step is to make sure that you apply the wet and forget directly to the organic growth like mold, moss, lichen, mildew or algae. The wet and forget is not effective on dirt or rust stains.
Most of the organic growth would be cleansed in only one generous application, but the lichen would require a 2nd application 15 min after the 1st one. So make sure to apply the second application if there is lichen. The lichen is peculiar and often after the first application opens up to show the root system.
The Next step:
Now you have to wait and watch. The surfaces on which you have applied wet and forget would be worked on by this solution. You should ideally wait for the rain after this and let Mother Nature do the cleaning.
With this all the hard work would be done by the rain and you can binge watch your favorite thriller in prime or Netflix. But if you are in no mood to wait, then give a week or two for the wet and forget to work its magic and then take your garden hose and give it a good rinse. You can also clean it by using a scrubber or a brush.