How can I delete all S Planner entries after synchronizing with iTunes backup?

[AliM999]

Help! I'm a beginner with the Galaxy S4 and have synchronized data from my previous iPhone backup on iTunes using the Easy Phone Sync app. All my old calendar data going back around 3 years is now appearing in S Planner and I can't manage to delete it.

I've tried Application Manager/S Planner/Clear data and Clear cache - but it hasn't worked.

Any help appreciated!!