The tag Office Open Specifications is dedicated to supporting issues related to open specifications. You can find open specifications here https://learn.microsoft.com/en-us/openspecs/
You inquiry is not related to open specifications. You may want to post your inquiry to stack overflow at the following link
https://stackoverflow.com/questions/tagged/openxml-sdk
Also there are samples at the following locations that you may find useful
https://learn.microsoft.com/en-us/office/open-xml/how-do-i
https://github.com/dotnet/Open-XML-SDK/tree/main/samples
I have removed the Office Open Specifications tag from your post.
Regards,
Obaid Farooqi - MSFT