The two boxes at first launch

From the app’s Help panel

The two boxes at first launch

Before anything else, Tentaku asks you to agree to its Terms — including automatic renewal of yearly plans and the arbitration agreement in section 16 — and its Privacy Policy, and to confirm you're 18 or older. Both boxes start unticked and Continue waits for both. The Terms and Privacy Policy links open them on tentaku.app in your browser; “Read offline copy” opens the copy built into the app, no internet needed. When the Terms change, a later version of the app asks you once more.