https://wccftech.com/windows-10-redstone-5-iso-files-17738/

Microsoft has today released Windows 10 Redstone 5 Preview Build 17738 ISO files. Today’s files come a week after the build was rolled out to the Insiders in the Slow ring. While Microsoft initially made Windows Insiders wait quite a long time, it appears the company is finally getting into the rhythm of getting ISO files out. As we get nearer to the final public release of Windows 10 October 2018 Update, we will hopefully be seeing more of these files.

ISO files for Windows 10 Preview Build 17738 are available for Enterprise, Home China, and general preview. You can use any of these to clean install Windows 10 Redstone 5 Preview Build 17738 after downloading them from here.