Regarding Upgrade Codeunit for business central cloud version

Hi Technicals,

I am working on Business Central Cloud Version.

Could you please help me to write the Upgrade codeunit for some tables data between two Extension.

I have running extention which is having 8 tables customized and 4 TableExt, Now I have another extenssion which is having those previous customization and extra 40 tables and some additional table ext. app.Json and launch.Json are same for both extension only the version is different.

Tast case which I done:

I have created the new sandbox instance to copy the data from production and I tried to upload my new extension which is giving me error to run the dataupgrade. then I tried to uninstall the previous version of extension and upload this new one which deleted the data for all the customized objects.