If you don't have a compelling reason to do something, you're at a severe disadvantage. It's hard to muster motivation without personal reasons for taking action.
Find a couple ways to fill in the sentence: "I want to do this because _________." Because I want to help someone, because I said I would do it, because I have a mortgage and 2 children...
Fortunately, we can act even though we're not feeling motivated. We've all done things because they needed to get done, or because we promised someone, or because we had nothing else to do.
When we take action, we get results. Those results can be internal—feeling good—or external—seeing numbers go up.
However, if we stumble and miss a day, that sense of momentum diminishes. Fortunately, if you don't give up, you can restart momentum. If you skip a day, always focus on resuming the next day. Don't let one bad day ruin a good endeavor.
Either way, we'll check the app again and again because it's so easy to get immediate feedback. All we need to do is tap a few times and we get a hit of dopamine (neurochemical associated with new).