An XML element, "person", that contains other elements:

You can define the "person" element in a schema as follows:

Notice the <xs:sequence> tag. It mean that the elements defined ("firstname" and "lastname") must appear in that order inside a "person" element.

Or you can give the complexType element with a name, and let the "person" element have a type attribute that refers to the name of the complexType (if you use this method, several elements can refer to the same complex type):