The entries can be read and written using the Strings [] property of the combo box, exactly the same way as for a list ring. So if you already have the entries in an array just create a property node, select the strings property, set it to write and wire the string array to it. If you don't have it as a string array you can e.g. use the read spreadsheet function and tell it that the delimiter is a comma and it will give you the string you need to wire to the property node.
