On official Chrome OS, you may run into trouble creating a USB installer. The simplest thing is still to use Windows or Mac, but should you be dedicated, valiently or foolishly, to using a Chromebook for this task, we can help you!
0) Download your cloudready image file
1) Open your Files app and find the downloaded file
2) Double click the file
3) This should "mount" the file on the left side of the Files app, appearing the same way a USB drive might
4) Go into that mounted zip file and find the non-zipped .bin file
5) Click and drag that file to your Downloads folder (this "transfer" may take a little time - keep an eye on the green bar in the bottom left corner of the File Browser)
6) Once the transfer finishes and is in your Downloads folder you can proceed with the use of Chrome Recovery Utility as described in our instructions, except using the newly unzipped .bin file.