Call (Consume) API using RestSharp in ASP.Net

Hello

i have this http code to send sms, how to call it on button click event please advice

var client = new RestClient("https://http-api.d7networks.com/send?username=mmvw6048&password=TPAEZfBB & dlr - method = POST & dlr - url =https://4ba60af1.ngrok.io/receive&dlr=yes&dlr-level=3 &from = smsinfo & content = This is the sample content sent to test &to = 000000000");
var request = new RestRequest(Method.POST);
request.AlwaysMultipartFormData = true;
IRestResponse response = client.Execute(request);

 its gives lots of error.