Hej igen jydepower.
The easiest is to use the trendview to display archived data.
Granted, it is not all kind of data that is suited to display in a trendview.
There is also a sample project on Siemens support on how to extract archived CSV data to display in WinCC Flex RT. However, the method used in the sample project is extremely crude.
Myself, I log some batch data upon event every 2 minutes by means of CSV scripting. You can find previous threads about this topic.
One advantage is that you can format the CSV file to you liking (with the net data in columns for example, rather than just one long sequence of values as the regular archiving in WinCC Flex). That makes it easy to display the logged data in a CSV viewer, or in Excel.
NB. Remember to write WinCC Flexible. WinCC and WinCC Flexible are not (yet) the same thing.