You need to activate the SYNC CALENDAR option on your Samsung Account on both devices. And, of course, have the Sync switch active as well. This should keep your calendars in sync between devices. The location might differ between the two devices, but it's in your phone's Settings under ACCOUNTS. There, just find the Samsung account you set up for it and click on the sync options.
Note that this applies for the default S Planner calendar. If you create events and save them to the LOCAL Calendar these will not be synced as they're for that device only. Also, if you're trying to sync another type of calendar like Google's or an Exchange account, the instructions would be similar but you'd need to select the appropriate account from your phone's settings.