The words in the book are arranged in a way to minimize confusion when pointing at them, allowing for dense pages without compromising on legibility. However, when you point at words or letters, you should try to keep your finger still for about half a second. Don't rush - the person you're talking to may have bad internet or high ping, which leads to missed words and forces you to repoint the sentence. It's more preferable to be slow at first until you learn the proper speed.
At the top of the page, there are handy words to manage your sentence. "cancel" and "repeat" can be used as "nevermind", "say again?", "i'll start over" while "general" and "specific" can be used to speak about a topic in a more general sense, like "I mean in general" or about a specific instance, like "that specific thought". "not" can be used to invert any word or verb if it's not available.
Pronouns are not included. It is assumed that you will point at the thing or person to talk about them. Saying "I love you" could be pointing "(point at me) LOVE (point at you)". If pointing is too specific and confuses people, try hovering the hand over the thing and do circular motions, this usually conveys "this thing".
More abstract conversation subjects, such as a hypothetical scenarios or objects, is a bit more difficult to refer to, but as long as you directly reply to the thing being talked about it should be fine. Otherwise, there are words to help describe: "place"/"thing"/"time", "this"/"there", "here"/"there", etc.
Possessives aren't included either, but they can be conveyed by reordering the sentence. Instead of pointing "(me) LOVE (you) CAT" (I love you cat?) try pointing "(you) CAT (me) LOVE" (You cat I love = your cat i love).