Generate classes from XML : xsd.exe not found
xsd.exe isn't in your path by default. It should be available in
C:\Program Files (x86)\Microsoft SDKs\Windows\v???\binWhat v??? actually is will vary depending on the version of the framework you have installed.
As Nguyễn Đức Tâm points out in their comment, you may find it inC:\Program Files\Microsoft SDKs these days, though it's still in Program Files (x86) for me.
Alternatively, search for Developer Command Prompt for VS20xx" in the start menu (wherexxdepends on the version of Visual Studio that you are running). This runs acmdwith your path set up to access development tools such asxsd` removing the need to find it.
Further adding to the above solution, run Developer Command Prompt for VS20xx as Admin.