You can load a saved search in your script, but what I like to do is use the chrome extension "NetSuite: Export as Script". This allows you to create a search an copy the code for the search to be in the script (this allows for better control over filters and columns). https://chrome.google.com/webstore/detail/netsuite-search-export/gglbgdfbkaelbjpjkiepdmfaihdokglp