I am looking to pass in multiple parameters to an examine search setup via ExamineSettings and ExamineIndex.

Below is the Razor script that is invoking the examine search. How can this be amended to include multiple search parameters?

@using Examine
@using Examine.SearchCriteria
@using UmbracoExamine
@{
  var rootNode = @Model;
  var searchString = Request.QueryString["searchstring"];
  var firstparameter = Request.QueryString["cpr"];
  var secondParameter = Request.QueryString["wt"];
  
  var searchProvider = ExamineManager.Instance.SearchProviderCollection["SiteSearcher"];
  var searchCriteria = searchProvider.CreateSearchCriteria(BooleanOperation.Or);
  var query = searchCriteria.RawQuery(searchString);
  var searchResults = searchProvider.Search(query).OrderByDescending(x => x.Score);
  <section>
    <article>
      @if(searchResults.Count() > 0){           
        <p>@searchResults.Count() results found for @searchString</p>
  <ul>
     @foreach (var c in searchResults){
     <li>
         <a href="@umbraco.library.NiceUrl(c.Id)">@c.Fields["nodeName"]</a>
     </li>
    }
        </ul>
      } else { <p>No results found.</p>  }
    </article>
  </section>
}