How to diagnose findings in ADDM report....

Hi There,
I need the assistance regarding findings in ADDM mean how diagnose it. Below are some finding in my ADDM report.

 
Finding 5: Hard Parse Due to Invalidations
Impact is .07 active sessions, 4.41% of total activity.
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Cursors were getting invalidated due to DDL operations. This resulted in
additional hard parses which were consuming significant database time.
 
   Recommendation 1: Application Analysis
   Estimated benefit is .07 active sessions, 4.41% of total activity.
   ------------------------------------------------------------------
   Action
      Investigate appropriateness of DDL operations.
 
   Symptoms That Led to the Finding:
   ---------------------------------
      Hard parsing of SQL statements was consuming significant database time.
      Impact is .29 active sessions, 18.36% of total activity.
 
 
Finding 6: Hard Parse Due to Sharing Criteria