Item code Generation

Dear codeag
thanks for your support.
I need from Erpnext to generate item code automatically , but this function does not work.
let explain:
when create new item the system should create the item code automatically but it is not created automatically I have to enter it manually. please see the next steps:

1- set naming item code

2- set item code to be createdautomatically

3- item code not created automatically