Follow the app identity
Begin with the app name and publisher. On the destination page, compare those details with the directory listing. Similar names and icons can belong to different products, so do not rely on the artwork alone.
Understand the destination
A directory button can lead to a store listing or publisher page. Those destinations control their installation flow and terms. Read the actual address and page details before taking the next step.
Respect device protections
Android includes protections for apps from different sources. Keep them enabled and take warnings seriously. See Android Help for current download guidance. The download walkthrough explains the steps inside this directory.