Hi.
The best way to transfer events is via Google Calendar. In other words if you synced your events from your old phone to Google then you can just sync on your new phone and all your events should appear.
On your old phone, do you know what kind of calendar you were adding your events to? By which I mean, in the add event screen, under "Calendar", what were you selecting? Was it a calendar from your Google account? If so, your events should have been synced to Google - you can check this by logging on to Google Calendar at
http://google.com/calendar.
If you were instead adding your events to a calendar called "PC Sync" or "My calendar", then that is not a calendar on your Google account. The "PC Sync" calendar is provided by HTC, and the "My calendar" entry is from Samsung, and if you have one of these or have been using any other kind of calendar, then syncing won't transfer your events. Instead, you may be able to find a backup app on the Play Store that will allow you to save your events and then restore them (to your new phone) if you still have the old phone. I'm afraid I can't recommend any particular backup app, though, as I haven't tried any myself.
Regards,
Oli.