Sounds like you are trying to tame your thoughts? It will not work, they just don't succumb to effort. Noticing them is all that is required and it's the only thing possible.

Instead of a how-to course, I suggest you look for Dharma talks on the practice of meditation. They can be very, very profound, there is a lot of material available. On just one site, the first one I looked at, spiritrock.org, there are over 100 talks for beginners.

A how-to app is doomed, which fact can be hard to grok. It's not like learning to drive or learning a programming language. A teacher or a retreat can be very helpful to get you past the initial missteps and misapprehensions.