Really need some help!  I created a Trigger that inserts records into a custom object.  The after insert is working.  However, the trigger just keeps inserting records.  Need help with the after update part.  How do I use Old.map New.Map in this trigger?  OppShipMonthAssociation__c is a junction object.  Ship_Month__c is a custom object.  Code is below:

trigger insertOppShipMoAssoc on Opportunity (after insert, after update) {
	List<OppShipMonthAssociation__c> osmas = new List<OppShipMonthAssociation__c>();
    for (Opportunity newOpportunity: Trigger.New) {
    	for (integer i = 0; i < newOpportunity.Number_of_Ship_Months__c; i++ ) {
            if(newOpportunity.Book_Ship_in_QTR__c == 'Yes' && newOpportunity.ForecastCategoryName == 'Commit') {
                Osmas.add(new OppShipMonthAssociation__c(
                        Name = newOpportunity.Id,
                    	Opportunity__c = newOpportunity.Id,
                		Ship_Month__c = ));
                
                
            }
		}
		 insert Osmas;
	}
}

Haiiiiii.............

i created differentobjects(applicant,recruiter,positions)and i created one VISUALFORCE TAB (jobs)--->so that it will open in vfpage----|  in that......

                 |

                 | 

       ______________________________________________________

       |     () applicant ----->|clicking on applicant page should open                 | 

       |     () Recruiter ----->|clicking on recruiter page should open                   |

       |                                                                                                                             |        

        -----------------------------------------------------------------------------------------------

How can i create radiobuttons and by clicking on that i want to open that{APPLICANT} page ------,recruiter page.......

 i created Applicant page in vf by taking the api names for(fields) which i had created in standard platform