If you use Calibre on your PC then you can transfer to your GloHD via wi-fi by starting the Calibre Content Server, take a note of the address and port it uses, and then download the books using the GloHD's web browser.
Edit: Another way is to upload your books to somewhere like DropBox and use your GloHD's web browser to download them from there. (But due to a recent change at DropBox you might need to switch from mobile to desktop view in the browser to download, see the screenshots in
this post.)