How to add Query and Header parameter to REST request using groovy script in SoapUI?

I'm new to Groovy scripting. I want to add Query (Style: QUERY, Level: RESOURCE) parameter and header (Style: HEADER, Level: METHOD) parameter as shown in below snap and want to select the Media-Type as "multipart/form-data" and also want to check the checkbox for "Post QueryString". How can I write groovy script to achieve above things?

I can't do it manually because of the automation framework that I'm using. I have single POST method for all my test cases (say e.g. for 25 test cases) and have to add or remove Query/header parameters depending on the requirement.