Here's a simple sample Continuous Flow Chart CFC program. It starts when the PLC application starts and increments a counter variable every second.
Note the PLCcounter variable should be added to the Global Variable List in your program. You can set this as a DINT. With it in the GVL, this will be available to other programs in the application.
For how to import, see this FAQ:
Here's a video it running within PAC IDE software:
Note a PAC320 hardware controller isn't necessary to run this. You can use an application with a CODESYS Control Win V3. Under Online > Simulation. Then you can after Build (F11), click Online >Login. This will create a virtual PLC and allow you to run PLC simulation (Play or F5). Here's a screen capture and project archive: