I'm currently only getting a 50% code coverage. How do I increase it to closer to 100%?

Thanks.

Trigger:

trigger PPM_CreateEquipmentDetailsRecord on PPM_Project__c (after update) {
    List <PPM_Equipment_Details_History__c> RecToInsert = new List <PPM_Equipment_Details_History__c> ();
    for (PPM_Project__c PPMP : Trigger.new) {
        PPM_Project__c beforeUpdate = System.Trigger.oldMap.get(PPMP.Id);
        if (beforeUpdate.of_Changes_to_Equipment_Details__c != PPMP.of_Changes_to_Equipment_Details__c) {
            PPM_Equipment_Details_History__c PPMBDH = new PPM_Equipment_Details_History__c ();
            PPMBDH.Equipment_Details_Old_Value__c = beforeUpdate.Equipment_Details__c;
            PPMBDH.Equipment_Details_New_Value__c = PPMP.Equipment_Details__c;
            PPMBDH.Project__c = PPMP.Id;
            RecToInsert.add(PPMBDH);
        }
    }
    try {
        insert RecToInsert; 
    } catch (system.Dmlexception e) {
        system.debug (e);
    }
}

Test Class:

@isTest
public class TestClass {
 
    Static testmethod void methodname() {
         List<PPM_Equipment_Details_History__c> recToInsert = new List<PPM_Equipment_Details_History__c>();
         List<PPM_project__c>  ppc = new List<PPM_Project__c>();
         List<PPM_project__c>  ppcnew = new List<PPM_Project__c>();
         for(Integer i=0; i<=10;i++) {
              PPM_project__c  ppc1 = new PPM_Project__c(name = 'i+s', requiredfields for inserting ppm project object);
              ppc.add(ppc1);
       }
       insert ppc;
       for(PPM_project__c pp:ppc) {
            pp.of_Changes_to_Equipmet_Details__c = "give the new value)
            ppcnew.add(pp);
       }
        update ppcnew;
        
              
}
}