facing issue while Implement the bulk addition of records to the detail [contact] of Account section

Hi community

I tried to add contact detail of account section using  a lookup where we can select multiple contacts for that account and add them in the detail using the following documentation 

https://academy.creatio.com/docs/developer/interface_elements/detail/implement_the_bulk_addition_of_records

But am not getting any lookup to add multiple records at once whereas it showing to add detail manually only once like this :

here is my code which I have written on my AccountContactDetailV2 :