Win-installer README.md: improvements and fix a mistake

src/WindowsInstaller/README.md

@@ -20,17 +20,17 @@ To build the installer you can do the following:
    (You can alternatively get nsProcess from https://nsis.sourceforge.io/NsProcess_plugin)
 7. Copy all FreeCAD files to the folder "~\FreeCAD"
    e.g. "C:\FreeCAD\Installer\FreeCAD"
-8. If you use compiled FreeCAD using another MSVC version than MSVC 2017, copy
-   its distributable DLLs to the folder FILES_DEPS (see step 2).
+8. If you use a version of FreeCAD that was compiled using another MSVC version than MSVC 2017,
+   copy its distributable DLLs to the folder FILES_DEPS (see step 3).
 9. Right-click on the file FreeCAD-installer.nsi and choose "Compile NSIS script"
-   to compile the installer
+   to compile the installer.
 10. The folder ~\MSVCRedist contains already all MSVC 2017 x64 redistributable DLLs necessary
    for FreeCAD 0.19dev. If another MSVC version was used to compile FreeCAD, replace the DLLs by
    the ones of the used MSVC. (They are usually available in the folder
    C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Redist\MSVC)
 
 For test builds of the installer you can turn off the compression. This speeds up
 the build time for the installer a lot but increases its file size. The compression
-is disabled by uncommenting the line
+is turned off by uncommenting the line
 SetCompressor /SOLID lzma
 in the file Settings.nsh.