No special app needed — everything is made to open with what you already have.
The main guide, the mini-guide, and the journaling prompts are regular PDFs, so they open on any phone, tablet, or computer. The prompts also come in print and typing versions, so you can journal on paper or on screen — whatever suits you.
The Reset Sheets and checklist are printable: use them with pen and paper, or fill them in on your device. No printer? No problem —they work either way.
The lock-screen reminders are image files, ready to save and set as your phone background in seconds (iPhone and Android versions included).
The audio reset is an MP3 you can play on any device, right out of the box.
The only piece that uses something extra is the Weekly Reset Dashboard: it opens in Google Sheets with a free Google account, and it comes with a short how-to guide that walks you through it. If you can open a PDF and tap a few cells, you're all set.