You might want to swap your modifier keys, based on what seems more convenient or comfortable to you. For example, when sharing a Windows keyboard with a Mac, using the Command-C can be tricky because the Windows key is in a different place than the Command key on a Mac. 

Follow the steps below to swap your modifier keys.

1. Open Synergy on your server computer.
2. Click the "Configure Server..." button on the main display.
3. You should now see all the machines that are configured on your network.
4. Double click on the machine whose keys you would like to edit (e.g. the Mac).
5. You will see a Screen Settings window.
6. On the right side you will see a vertical list of all the modifier keys.
7. You change the keys based on what you want which key to do.
8. Click OK to close the Screen Settings window.
9. Then click OK again to close the Server Configuration window.
10. Click Apply to save your new configuration.