Type "namespace" is not declared, when importing namespace

Firstly, im vrey very new to xml and schemas, so apologies if this question is brutally basic.
I have created a schema, and am importing another schema that contains a complex type. I am getting the error "type http://myNamespace2.com/songSchema is not declared"
I have followed a number of tutorials and cant see where i have gone wrong. can anyone advise?

Here is the main schema. The second schema is the one i am importing. Thanks all.

    targetNamespace="http://myNamespace1.com/XMLSchema1"
    elementFormDefault="qualified"
    xmlns="http://myNamespace1.com/XMLSchema1"
    xmlns:mstns="http://myNamespace1.com/XMLSchema1"
    xmlns:xs="http://www.w3.org/2001/XMLSchema"
    xmlns:sn="http://myNamespace2.com/songSchema">
 

targetNamespace="http://myNamespace2.com/songSchema"
elementFormDefault="qualified"
xmlns="http://myNamespace2.com/songSchema"
xmlns:mstns="http://myNamespace2.com/songSchema"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
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