Hi All,
i am new to apex programming. in apex code below i have to pass one dml statement(opplist) to pass account id along with json string (parentOppJson) can anybody let me know how to do that.

/**
 * Controller used by the "scheduleOppsLwc" Lightning Web Component.
 
 * @since   2021-10-05
 * @version 2021-10-05
 */
public class ScheduleOppsCC {

    /**
     * Creates new child installment Opportunities related to the Opportunity
     * used for the "Schedule Opportunities" quick action and updates the parent
     * as needed to CPQ-related details.
     * @param   parentOpp       ID of Opportunity from quick action context
     * @param   parentOppJson   JSON string-representation of the parent opportunity with new values for update
     * @param   childOppsJson   JSON string-representation of a list of child opportunities to create
     */
    @AuraEnabled
    public static void createChildrenUpdateParent(String parentOpp, String parentOppJson, String childOppsJson) {
    
     system.debug('--> Schema.Opportunity.SObjectType '  + Schema.Opportunity.SObjectType);
     
        
     Id parentOppId = Id.valueOf( String.escapeSingleQuotes(parentOpp) );
     system.debug('--> parentOppId '  + parentOppId);
     
        
       if ( Schema.Opportunity.SObjectType == parentOppId.getSObjectType() )
       
      
        {
           try {
           
            List<Opportunity> parentOp = (List<Opportunity>)JSON.deserialize(parentOppJson, List<Opportunity>.class);
         System.debug( '-> parentOp = ' + parentOp );
         
           //List<Opportunity> oppList = [ SELECT Id, AccountId , RecordTypeId , StageName, Name,CloseDate  FROM Opportunity  WHERE Id = :parentOppId ];
           
                                          
                                           
                                           
        if ( (parentOp != null) && !parentOp .isEmpty() ) {
            List<Opportunity> childOpps = (List<Opportunity>)JSON.deserialize(childOppsJson, List<Opportunity>.class);
            system.debug('--> childOpps after deserialize ' + childOpps);
            List<Opportunity> insertingChildren = new List<Opportunity>();
            for ( Integer i = 0; i < childOpps.size(); ++i ) {
           
            
              Opportunity opp = new Opportunity(AccountId = parentOp [0].AccountId, RecordTypeId = parentOp [0].RecordTypeId  );
              opp.Is_Child__c = true;
              opp.Parent_OpportunityID__c = parentOppId;
              opp.StageName = parentOp[0].StageName;
              opp.Name = parentOp[i].Name;
              opp.CloseDate = childOpps[i].CloseDate;
              opp.Primary_Contact__c = childOpps[i].Primary_Contact__c;
              opp.First_Installment_Date__c = parentOp [0].First_Installment_Date__c;
              opp.Installment_Period__c =  parentOp [0].Installment_Period__c;
              opp.Last_Installment_Date__c = parentOp [0].Last_Installment_Date__c;  
              opp.Number_of_Installments__c = parentOp [0].Number_of_Installments__c; 

              opp.MINT_Lines_Magenta_IoT__c = childOpps[i].MINT_Lines_Magenta_IoT__c;
              opp.Probability = parentOp [0].Probability;
              opp.Scheduled_as_Child__c = childOpps[i].Scheduled_as_Child__c;
              opp.Scheduled_with_Children__c = childOpps[i].Scheduled_with_Children__c;
              opp.Schedule_Type__c = parentOp [0].Schedule_Type__c;
              
              opp.Voice_Lines__c = childOpps[i].Voice_Lines__c;
              opp.Yellow_IoT_Lines__c = childOpps[i].Yellow_IoT_Lines__c;                     

                // update opp with records from childOpps[i] //
               
                insertingChildren.add(opp);
                 
            } 
            System.debug( '-> insertingChildren1 = ' + insertingChildren);
            try{
                   insert insertingChildren;
                    System.debug( '-> insertingChildren2 = ' + insertingChildren);
           } catch(DmlException e) 
           { System.debug('The following exception has occurred: ' + e.getMessage()); }
        } 
              
             
                List<OpportunityLineItem> oliList = [ SELECT Id
                           FROM OpportunityLineItem
                          WHERE OpportunityId = :parentOppId ];
                System.debug( '-> oliList = ' + oliList );
                delete oliList;
                /* insert (List<Opportunity>)JSON.deserialize(childOppsJson, List<Opportunity>.class);
                delete [ SELECT Id
                           FROM OpportunityLineItem
                          WHERE OpportunityId = :parentOppId ]; */

                
                   for( Opportunity op : parentOp  ){
                    
                   op.StageName = 'Discovery';
                 }
                
                
                System.debug( '-> parent = ' + parentOp );
                update parentOp  ;
          } catch (Exception ex) {
                System.debug( 'EXCEPTION @ ' + ex.getLineNumber() + ' (' + ex.getLineNumber() + ': ' +
                        ex.getMessage() + '): ScheduleOppsCC.createChildrenUpdateParent()\n -> parentOpp = ' +
                      parentOpp + '\n -> parentOppJson = ' + parentOppJson +
                       '\n -> childOppsJson = ' + childOppsJson);
              throw new AuraHandledException('An error occurred, please reach out to your administrator for assistance.');
            }
       }
       throw new AuraHandledException('This action is only available for Opportunity records.');
   }

}