First, you check in the index of the dictionary if the symbol is there.
If not there, check the one-word symbol in the search (find) function of the document.
If no results, ask for the meanings of the symbol on the Dream Interpretation Community Forum.
Take note that the dream dictionary is updated once a year. When more symbols are added and the new update is released, everybody is notified so that they can download the latest (new) version of the dictionary.