External table is not in the expected format

See https://support.smartbear.com/testcomplete/docs/testing-with/data-driven/drivers.html 

It will be similar to,

function main()
{
    const sheet = Project.Variables.Var1;
    sheet.Reset();
    while (!sheet.IsEOF()) {
        // Read your inputs
        var id = sheet.Value("ID");
        var obj = sheet.Value("JSON");
        
        // Populate your fields
        
        // Move to record
        sheet.Next();
    }
    sheet.Disconnect();    
}