1. You would literally say, 'I'm about to drink a coffee.' or 'I'm going to drink coffee.' 2. Your daughter, 'rips it off the branch.' 3. She, 'throw some dough.' 4. You would say, 'Don't throw it on the floor.' For 2, 3 and 4 you are using present tense. However for speaking in the third person i.e. she/he/it you need to add an -s. So instead of, 'I throw the dough' it becomes, 'She throws the dough.' Hope that helps :)

You have created a good statement using to be + infinitive, but this construction is used only in formal English, especially writing. Your situation is very informal and so your first option - about to + verb - is perfect. "rip the leaf off the tree" is probably a bit strong unless she was very angry. If her movement was normal, you could just say "take / pick a leaf off / from the tree". "throw" is the correct verb. In your case, your identified where she wanted to throw the dough (on the floor). "throw away / out" is used as a synonym for "dispose of".