Download the installer, run it, done. No administrator privileges needed.

Go to the download page and click Download (.exe). The file is called zonkod-latest.exe.
Find the downloaded file (usually in your Downloads folder) and double-click it. Windows may show a blue "Windows protected your PC" screen.
ClickMore info, thenRun anyway. This is normal for apps not yet listed in the Microsoft Store.
Choose your language and install location (default is fine). ClickInstall. You can choose to install for just yourself or for all users.
After install, find Zonkod in yourStart menu. You can also pin it to your taskbar or desktop. No account, no sign-up.
Yes. The installer is code-signed. Windows SmartScreen may warn you because the app is new and not yet widely downloaded; this reputation builds up over time.
Zonkod checks for updates automatically. When a new version is available, you'll get a notification. You can also re-download and reinstall; your settings and cached maps are preserved.