Hi Susan McKean,
Thanks for your post. Based on my research, can I know if you are using the version of Windows 10 Enterprise LTSC? If so, I would recommend you follow the instructions provided in the article "How to Add/Install Microsoft Store on Windows 10 LTSC or LTSB Editions": https://www.geeksforgeeks.org/how-to-add-instal...
Also, the quick assist installation way is from MS store only from the official article.
Solve PC problems remotely using Quick Assist - Microsoft Support
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.
Best Regards,
Ian Xue
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