Does your PC have the ability to connect to the PLC(s) that will be used in the application?
If so do these steps first:
On the main menu bar go to Link > Options >
And click on the tick box at the bottom of the dialog box "Send to Emulator".
That will enable the adjacent button Configure for the emulator communication options. If your project communicates using Ethernet, assign the Ethernet Port 1 (or Port 2 if you're using Port 2) to the PC adapter where the PLC can be accessed.
If your project uses the serial ports, you need to know how they are numbered on your hardware which you can find by viewing the Communication setup and highlighting the device and then look at the lower left edge of the software. The emulator has numbers that correspond to all the possible serial ports for any device it can emulate. With serial comms and the emulator, you will have to stop any PLC software drivers that might tie up the PC serial port that you intend to use for the emulator.
Hit okay to close those two windows.
Ensure the Emulator icon (just to the left of the lightning bolt icon on the menu bar) is toggled on.
Click on the lightning bolt or F9 to update the device (now pointed at the Emulated hardware) with the application.
In the 3.2 Emulator, to close the emulator, you can Click on the emulator icon on the menu bar (just left of the update lightning bolt). To reopen it, just turn the emulator icon back on and hit the lightning bolt.
Note that without having the ability to communicate to the devices, the emulator will show (just like real hardware will) dashes for display values that cannot be retrieved and object animations and states that can't get the source data may appear blank or without colors, etc.