Cannot open source file "Blueprint/UserWidget.h"

Hello, I am trying to following this tutorial in UE 4.9 version. I have written everything as same as her but the “Blueprint/UserWidget.h” source file cannot be found. I have checked the other answer relating this same issue but they didn’t helped. These answers didn’t helped:

1-> https://answers.unrealengine.com/questions/241263/include-blueprintuserwidgeth-missing.html

2-> https://answers.unrealengine.com/questions/245736/cannot-open-source-file-blueprintuserwidgeth.html

Note: In second answer, I couldn’t find the option named “Generate visual studio project files” when I right clicked the .uproject file.