To build gridx, copy gridx.profile.js to your/dojopath/util/buildscripts/profiles/, then run:

your/dojopath/util/buildscripts/build.bat --profile gridx --release

When the building process is completed, a gridx-release directory will be created.
Copy test_grid_build.html and test_grid_build.js into gridx-release and access test_grid_build.html through your browser.