Set Jenkins parameters from AWS Parameter Store

I am trying to get environment variables from AWS Parameter Store for Jenkins CI/CD pipeline. I have assigned IAM role to this instance, so no credentials are required to be passed. This is my parameter

{
    "Parameters": [
        {
            "Name": "Test",
            "Type": "String",
            "Value": "Hello World",
            "Version": 1,
            "LastModifiedDate": 1639400445.755,
            "ARN": "arn:aws:ssm:########:#########:parameter/Test",
            "DataType": "text"
        }
    ],
    "InvalidParameters": []
}

I have installed AWS Parameter Store Build Wrapper plug-in and using withAWSParameterStore method to capture the value.

This is how I am trying

val = withAWSParameterStore(namePrefixes: "Test", regionName: '#######'){}
echo val

Variable var returns null.

How do I capture the value "Hello World" here.

IAM role assigned to EC2 instance where Jenkins is running doesn't help. We still need to create a credential in Jenkins with IAM Access and Secret key. In order to capture the data, you may follow something like the below:

withAWSParameterStore(credentialsId: 'myjenkins-id', 
namePrefixes: 'Test', 
regionName: '########') { 
         echo "${env.Test}" 
         echo "${env.TEST}" 
         echo TEST} ```