The whole point of this site is to grow your vocabulary and build experience with the German language through consuming German content. The result of your activities is your own personal dictionary. By clicking on "My words" in the menu, you can manage your personal dictionary.
You can sort the words and search for words. You can click on a letter to show only words starting with that letter. In the list of words, you can click on a word and modify the data for that word.
Beside these standard features, you have several other options:
Init - Maybe you are not a beginner, so you don't want to start from the very beginning in building your dictionary. This option allows you to fill your dictionary with preset words. Remember, language dictionaries already exist. The whole point of this site is to build your own dictionary and practice words. The dictionary is not the goal, it is a learning tool.
Import - You can import the words that you have exported.
Export - You can export the words from your dictionary.
Test - Maybe you have 10000 words in your dictionary and all the words are marked as known. Well, from time to time you might want to update your memory. This option allows you to select a random set of words that will be used in the practice section of this site.