How to create Datasource through AWS Machine Learning SDK

I am trying to create a Datasource using AWS Machine learning SDK. I have a data set and its corresponding schema.Both are stored in S3.Initially i thought that i just need to provide column names in schema. so initially my schema looked like this -

ColName1,ColName2,....,ColNameN

Later i realized that i need to put the datatype into the schema not label names.so i changed my schema to

Number, String,....,String

Still i am not able to create datascource because of improper schema. I am getting this error -

FAILURES (1): There was an error trying to parse the schema: 'Unexpected character ('s' (code 115)): expected a valid value (number, String, array, object, 'true', 'false' or 'null') at [Source: java.io.StringReader@3ef68a3a; line: 1, column: 2]' 

Now i think that i need to provide the schema in json format, though i am not sure,can someone please provide example of what to put in schema ?