When searching for the installer, you’ll see two options. Here’s why the is the top choice for Windows 7:

Many legacy Windows 7 machines have trouble connecting to modern Wi-Fi or require specific drivers to get online. The offline installer contains all the files in one package (approx. 66MB).

If the installer says a newer version is already installed, you likely have .NET 4.6, 4.7, or 4.8. You don't need to downgrade; newer versions are generally backward compatible.