need explanation

• Use the block "ChangeMilliSec_S7-300" [FB61] for S7-300/400

1. "Copy the "STEP7-TIA-Portal_Change_Millisec.zip" file into a separate directory", you have done this step as you copied the file to your desktop.
   
   
2. "and then start the file with a double-click".In this case, as the file is the ".ZIP" file it will ask you retrieve the file to a place in your desktop or somewhere else.
   
   
3. "The library now unpacks automatically with all the associated subdirectories." the needed files are somewhere stored and you know the place of storage e.g Desktop.In my case, I could retrieved the files with WINRAR and there was no need to automatic unpacking.
   
   
4. "Then you can open the library in STEP 7 (TIA Portal) and process the three functions."now you have access to a file that can be processed by TIA V12.

I hope every thing is clear now