Possible to select multiple options on Widex "Zen" for Tinnitus?

I am preparing for an appt this coming week to remotely fit my new Widex Moment Sheer 440’s. I watched the video re choosing a helpful tone and will do that again, as one did seem to quiet it down. I read a brief sales support guide that left me with a couple questions.

It seems that there are two ways to use the “tone” you choose: As a constant background masking setting kind of like white noise or on demand. Can a user switch back and forth or does the tech have to make changes?

Does the user have the ability to select different sounds or do I have to pick one and the tech programs my aid to use it?