To find a symbol from anywhere in the program, press the F2 key to get to this page, then type in the name or some keyword to identify it, and press enter or click OK.
That will find the first example of that search, with a blue hotword to the right. Click that hotword to go to the symbol and its related materials. In some cases, the entries are just definitions of abbreviations with no associated symbols. In these cases there are no hotwords. The instructions include tips on efficient searching techniques.
In this example, we have searched for the topic of "high water" and found a symbol section called "H20" includes this. Rock symbols and all others related to the "shoreline datum" are heavily dependent on our understanding of the local mean high water value and where to find it. A "rock awash," for example, is, by definition, exposed at 0 tide height (the "sounding datum") but must be exposed at mean high water (the shoreline datum in most areas).