Need designing Mobile App Experiences with Landing Pages and Walkthroughs

When developing a single-page mobile app in bubble.io, I’ve implemented a landing page that greets users when they visit via their browser. This landing page includes a prominent Call-to-Action (CTA) button encouraging visitors to download the app from both app stores, along with informative content designed to persuade visitors to download the app.

However, once users have downloaded the app and visit it from their device, I want to hide this landing page to provide a seamless app experience. Additionally, I have a walkthrough section intended to guide users through the app after downloading, but I only want it to be visible when users access the app from their device, not from their browser.

What would be the most effective approach to achieve these goals, ensuring a smooth transition from the landing page to the app interface and displaying the walkthrough section only to users accessing the app from their device?