How to use the docusign-esign.SignHere function in docusign-esign

doc.setName('TestFile.pdf'); // can be different from actual file name
      doc.setDocumentId('1');

      var docs = [];
      docs.push(doc);
      envDef.setDocuments(docs);

      // add a recipient to sign the document, identified by name and email we used above
      var signer = new docusign.Signer();
      signer.setEmail(signerEmail);
      signer.setName(signerName);
      signer.setRecipientId('1');

      // create a signHere tab somewhere on the document for the signer to sign
      // default unit of measurement is pixels, can be mms, cms, inches also
      var signHere = new docusign.SignHere();
      signHere.setDocumentId('1');
      signHere.setPageNumber('1');
      signHere.setRecipientId('1');
      signHere.setXPosition('100');
      signHere.setYPosition('100');

      // can have multiple tabs, so need to add to envelope as a single element list
      var signHereTabs = [];
      signHereTabs.push(signHere);
      var tabs = new docusign.Tabs();
      tabs.setSignHereTabs(signHereTabs);
      signer.setTabs(tabs);

      // add recipients (in this case a single signer) to the envelope
      envDef.setRecipients(new docusign.Recipients());
      envDef.getRecipients().setSigners([]);