I try to open the C++ first person thing and this happens

An error occurred while trying to generate project files.

Running C:/Program Files/Epic Games/UE_4.14/Engine/Binaries/DotNET/UnrealBuildTool.exe -projectfiles -project=“C:/Users/User/Documents/Unreal Projects/BigProject/BigProject.uproject” -game -rocket -progress
Discovering modules, targets and source code for project…
UnrealBuildTool Exception: ERROR: Windows SDK v8.1 must be installed in order to build this target.

I tried to open the C++ one and I tried loading the first person one then it would bring this up…

Here you go:
Error windows SDK v8.1 must be installed in order to build this target