Important!: To start a wordweb you have to add a class first
Open a book in your book overview. Long press on the page. You'll see two options: "note" or "WordWeb". Choose "Wordweb". Enter the topic of the wordweb and press save. You can start the wordweb at any time by opening it at a later time.
Once you press "start" your students will automatically join the wordweb. The student input will appear in your screen as numbered bubbles. If a word has been suggested by multiple students, the bubble will grow and the number willl increase.
If you're ready to stop the wordweb, simply press "close wordweb". Now, you'll be able to open the bubbles and see the input. You can even who suggested the word by tapping on it.
If you're done with the wordweb you can exit the screen by pressing "close wordweb"
Here's a live instruction.