form in excel

Hi,

A list of students' names is already typed in Table1 in the DATA sheet.

I designed a form so that after entering the items and pressing the Save button, that information is saved in a table in the DATA sheet, But there are problems that I cannot solve:

• If a new student is entered in "new student", the entered name will be compared with the existing names in first column of Table1 and added to the end of the list if it is not duplicated. If duplicated, give an error message.
• The first column of Table1 should be automatically considered as the cmbNameSTU combo box list.
• If the student's name is typed in "Name" (and not selected from the list), when the Save button is pressed, the typed name will be compared with the existing ones, and if it is not in the list, it will give an error message.
• While typing in "Name", the combo box will open and the items that start with the typed character will appear automatically.

File attached.