Hi GailThomas3,
Thank you for reaching Microsoft Community.
What are these apps that you are trying to install?
I believe your phone is an Android phone, correct? Your Surface Pro 5thgen is a Windows 10 device and applications on Google Play are for Android devices. Please check with the app developer if a version for Windows 10 is available. You may also use a third party emulator to run those Android apps in Windows 10 or you may check the Microsoft Store app on your Surface to see if the app you are trying to install is also available for your Surface.