1-In the parent form, include a button or a link that navigates to the child list. Pass the parent ID as a request parameter in the URL, for example:/childListPage?id_parent={parent_id} 2-In the child list, modify the Add button to include the id_parent parameter in its URL. Use a distinct parameter name (e.g., id_parent) to avoid conflicts. Example URL:/childFormPage?&id_parent="requestParam.id_parent" 3-In the child form, add a hidden field called id_parent. Set the default value of this field to the id_parent parameter from the URL using a hash variable:#requestParam.id_parent# 4-When displaying the child list, filter records to show only those related to the current parent. If using a JDBC datalist binder, add a filter condition in the query:SELECT * FROM child_table WHERE c_id_parent = '#requestParam.id_parent#' or if you are using a simple list use the extra filter condition like c_id_parent = '#requestParam.id_parent#'