As discussed earlier, A landing page is where your users land in your app. You can create multiple landing pages when using the Stores plugin (If you would like to know more about Landing Pages, refer to earlier sections that explain them in greater detail), and set one of them to be 'Start Page' so that your users when they log into your app will reach the landing page.
Then why create many landing pages? You may need them for different purposes, like A/B testing, a dedicated landing page for promoting a new product launch, or you want some content completely out of the rest of your app content and give access to only a selected few, or any similar purpose your business might need them.
Follow the steps to set a Landing Page to be your Start Page. Learn how to create Landing Pages