Sign up with a card. The first seven days are free, and the trial is the full app — there is no cut-down version to graduate out of.
Tell the app your goal: why you're learning, and how many minutes a day you can give it. Your lessons are shaped by both.
Do the first lesson. One a day after that, each written from the last.
Day 8 is the first charge. Cancel any time before then in Settings and the card is never charged.