plz help me how to write test case for my trigger

trigger Dev_update_Appt on Appointment__c(after update)
{
public list<appointment__c> apps {get;set;}  
public list<appointment__c> apps5 {get;set;} 
apps5 = new list<appointment__c>();
apps = new list<appointment__c>();

Map<ID , appointment__c> mapAppiontment = new MAP<ID , appointment__c>([select ID,Account__c,Name,Branch__c,Doctor__c,Appt_Date__c, Dev_Parent_Appt__c from appointment__c where 

id in: trigger.old]);

List<appointment__c> listApp = new List<appointment__c>();

MAP<ID , List<appointment__c>> mapAPPID_List = new MAP<ID , List<appointment__c>>();
for(appointment__c appObj : [select ID,Account__c,Name,Branch__c,Doctor__c,Appt_Date__c,Dev_Parent_Appt__c from appointment__c where   Dev_Parent_Appt__c in: 

mapAppiontment.keyset()])
{
  if(mapAPPID_List.containskey(appObj.Dev_Parent_Appt__c))
     {
         listApp = mapAPPID_List.get(appObj.Dev_Parent_Appt__c);
     }
   else
     {
        listApp = new List<appointment__c>();
     }
  
  listApp.add(appObj);
  mapAPPID_List.put(appObj.Dev_Parent_Appt__c , listApp);

}

for(Appointment__c o:Trigger.old )
{   

if (Trigger.isUpdate)
{
appointment__c  app1 = mapAppiontment.get(o.id);
List<appointment__c>  app  = new List<appointment__c>();

if(mapAPPID_List.containsKey(app1.id))
   app = mapAPPID_List.get(app1.id);

for(appointment__c ap:app)
{
ap.branch__c=app1.branch__c;
ap.Doctor__c=app1.Doctor__c;
ap.Appt_Date__c=app1.Appt_Date__c; 
apps.add(ap);
}
} 
}
update apps;
}

 my test case i have written i am getting 60 percent 

@isTest
private class updateclass
{

static testmethod void TestController() 
{

Staff__c s1 = new Staff__c();
      s1.name='Rahul';
      s1.Mobile__c='9849098490';
      insert s1;


Branch__c b = new Branch__c();
b.Name = 'Test';
b.Region__c = 'Market Price';
insert b;


Account a = new Account ();
a.LastName = 'Test';
a.Branch__c = b.id;
a.PersonMobilePhone = '9550412970';
insert a ;







    Appointment__c app2 = new Appointment__c();
      app2.account__c=a.id;
      
      //app2.Dev_Parent_Appt__c=app1.id;
      
      
         app2.from__c='6';
        
        app2.from_min__c = '00';
        app2.Appt_AM_PM__c='PM';
        app2.Appt_Date__c=date.ValueOf('2011-05-21');
        app2.Appt_Hour__c='9';
        app2.Appt_Minute__c='80';
        app2.RecordTypeid='012N0000000CgZ2';
       
        app2.Branch__c=b.id;
        app2.to_Min__c='40';
        app2.to__c='7';
          insert app2;
       update app2 ;
       
      
       }
       }

 plz help me to resolve my issue