I'm looking for some guide/tutorial on how to best merge 2 instances of Sugar (i.e DEV and PRD)
SugarCRM Enterprise, Version 188.8.131.52 (Build 1163)
We do not really have any direct documentation on merging instances. Are you trying to merge data (the database) or customizations as well? We do have documentation on Importing and Exporting. You can export the data from the demo database and then import the CSV into the production database. This is likely the best bet for merging data.
Retrieving data ...