The width and height can be changed using the two dropdown boxes in the options section. Currently the minimum size is 5 and the maximum size is 20. The default size is 12. Size will not automatically update, you will have to click generate yourself for an update.
To add words to the word list just type a new word in the new word input box located in the options section. All words currently in the list are available in the current word list section under the options section New words are not automaticly added to the generated output and you will have to click generate yourself. To remove words from the current list just click the corresponding X.
By having shuffle turned on, the algorithm will shuffle to word list before placing the words. See Handling Words
To generate the word search click the generate button. The algorithm has 5 attempts to place the word. If it is unable to place a word then the Missing words section will appear. Words can be placed in the following orientation vertical, horizontal and diagonal.