How to get an API response visual studio

I've got the below API test but i can't find a parameter that will pass for my Then scenario. I've got a specflow which is passing and only failing at the Then stage can someone suggested what i could include. Any help will be appreciated

 namespace APITesting
{
    using System.Net;

    using NUnit.Framework;

    using RestSharp;
    using RestSharp.Extensions.MonoHttp;
    using TechTalk.SpecFlow;

    [Binding]
    public class ApiTestsSteps1 : BaseSteps
    {

        private const string SearchTerm = "red";
        private const string Limit = "10";

        /// <summary>
        /// Make a request to 'GET /product/search/V1'
        /// Accept: application/json
        /// Parameters - ?store=1&lang=en&currency=GBP&q=red&offset=0&limit=10
        /// </summary>

        [Given(@"I call Search API without parameter")]
        public void GivenICallSearchApiWithoutParameter()
        {
            this.Request = new RestRequest(Method.GET);
            ////Add the Accept Type and Request Parameters here
            ScenarioContext.Current.Add(RequestKey, this.Request);
        }

        [Then(@"API returns response")]
        public void ThenAPIReturnsResponse(Table table)
        {
        **** Parameter ****    
        }


    }
}