The SiteFinder app offers Android users a way to access the club's web site through a single click on their phone's screen. The app will handle both portrait and landscape orientations on your smartphone, and it also supports zooming of the display window.
Since this app is not posted to the Play Store, Google is very likely to warn you against installing "third-party" apps. But, rest assured, you have downloaded the APK file directly from OPCUG's web site so it is perfectly safe. However, you need to install the app through a process known as
Essentially, this means telling your phone's security system that it is OK to "Allow installation of apps from unknown sources". All this means is that the source is unknown to Google, it's not unknown to you!
The specific manner in which this setting needs to be modified is dependent on your model of smartphone and its version of Android. You may be able to navigate to Settings – Security – Unknown sources to find the toggle. If not, check your phone's user's manual or seek specific instructions through a web search.