List to store values apart from the post construct method in data table primefaces

Question

I have a post construct method which is used to display data in datatable.but i want another list to store new row values in data table using primefaces and JPA.

<p:panel header="Edit" styleClass="p-mb-3" modal="true" widgetVar="w_edit" visible="false" >

             <p:dataTable value="#{bookikgRouteDetailAction.itRoute}" var="bookRou" id="tabb" widgetVar="t_edit">
               <p:column headerText="IcStatus">
           
            
            <p:selectOneMenu value="#{bookikgRouteDetailAction.bookRoute.icStatus}" id="statusId">
                        <f:selectItem itemLabel="#{bookRou.icStatus.name}" itemValue="#{null}" />
                        <f:selectItems value="#{bookikgRouteDetailAction.icStatusList}" var="_regg"
                            itemValue="#{_regg}" itemLabel="#{_regg.name}">
                        </f:selectItems>
                        <f:converter converterId="javax.faces.StatusConverter" />
                        <p:ajax  process="@this"  event="change"  />
            </p:selectOneMenu>
            
            </p:column>
            
           <p:column headerText="ItBooking">
               
            <p:selectOneMenu value="#{bookikgRouteDetailAction.bookRoute.itBooking}" id="bookingId">
                        <f:selectItem itemLabel="#{bookRou.itBooking.status}" itemValue="#{null}" />
                        <f:selectItems value="#{bookikgRouteDetailAction.itBooking1}" var="_regg1"
                            itemValue="#{_regg1}" itemLabel="#{_regg1.status}">
                        </f:selectItems>
                        <f:converter converterId="javax.faces.BookingConverter"/>
                        
                          <p:ajax  process="@this"  event="change" />
                        
                </p:selectOneMenu>
            </p:column>
               </p:dataTable>           
             <p:commandButton value="Add" icon="ui-icon-add"  
                action="#{bookikgRouteDetailAction.add()}" process="@this" 
                update="tabb">  
    </p:commandButton>  
    
        <p:commandButton value="save"  action="#{bookikgRouteDetailAction.save()}"  process="@this" />
         </p:panel>