diff --git a/src/doc/manual/user-guide/building.txi b/src/doc/manual/user-guide/building.txi
index 90ad8a02f..25d8f211a 100644
--- a/src/doc/manual/user-guide/building.txi
+++ b/src/doc/manual/user-guide/building.txi
@@ -71,12 +71,13 @@ Top level in: #<process TOP-LEVEL>.
 You need Microsoft Visual Studio 2015 or better to compile ECL,
 which flavor(Professional, Community, etc) does not matter.
 
-You also need @uref{http://yasm.tortall.net,yasm},
+You also need @uref{http://yasm.tortall.net,yasm} optionally to build gmp,
 fetch yasm-1.3.0-win64.exe and yasm-1.3.0-win32.exe,
-put them in your system PATH directory.
+and put them in your system PATH directory.
 
-Open a console window,
-and run vcvarsamd64.bat or vcvars32.bat to set up your build environment.
+In the Visual Studio's startup menu,
+click @uref{https://docs.microsoft.com/en-us/dotnet/framework/tools/developer-command-prompt-for-vs,Developer Command Prompt for Visual Studio}
+to open the console window.
 
 @enumerate
 @item