Hi everyone

I am want to implement a pdf search using UmbracoExamine.Pdf, but I don't really know how to do it. I have used the class from this blog, but it doesn't work. The documentation I found on examine pdf is for a multi index searcher, but I don't want that. This is how my code looks like so far:

 [HttpPost]
    public ActionResult pdfSearch(string searchTerm)
    {
        var test = querySearchIndex(searchTerm);
        return Json(test);
    }

    private ISearchResults querySearchIndex(string searchTerm)
    {
        if (ExamineManager.Instance.TryGetIndex("PDFIndex", out var index))
        {
            ISearcher searcher = index.GetSearcher();
            IQuery query = searcher.CreateQuery(null, BooleanOperation.And);
            string searchFields = "fileTextContent";
            IBooleanOperation terms = query.GroupedOr(searchFields.Split(','), searchTerm);
            return terms.Execute();
        }
        else
        {
            throw new InvalidOperationException($"No Index found with name PDFIndex");
        }

    }

What am I doing wrong? Thanks