Not able to impliment sign-in with twitter and linkedin

Question

hey I am sorry if this has been asked before I am new here i don't know how it can be done I successfully impliment login with facebook and sign in with gmail but not able to sign in with twitter and linkedin don't know why? please help

For twitter i visited https://dev.twitter.com/web/sign-in don't no how to use it also https://dev.twitter.com/web/sign-in/implementing.

And for linkedin

 http://stackoverflow.com/questions/18463713/customizing-linkedin-login-button/39826764#39826764

but this not even display linkedin button or image always display blank page

i spend 4-5 hours found nothing how to do them please help

Class 'OAuthSignatureMethod_HMAC_SHA1' not found

i tried various examples and m getting same error in each case don't know why? help me please

 function __construct($consumer_key, $consumer_secret, $oauth_token = NULL, $oauth_token_secret = NULL) {
    $this->sha1_method = new OAuthSignatureMethod_HMAC_SHA1();
    $this->consumer = new OAuthConsumer($consumer_key, $consumer_secret);
    if (!empty($oauth_token) && !empty($oauth_token_secret)) {
      $this->token = new OAuthConsumer($oauth_token, $oauth_token_secret);
    } else {
      $this->token = NULL;
    }
  }

if i used require_once('OAuth.php'); then doesnot not display Fatal error: Class 'OAuthSignatureMethod_HMAC_SHA1' not found but display errors like Undefined index: oauth_token on

 function getRequestToken($oauth_callback) {
    $parameters = array();
    $parameters['oauth_callback'] = $oauth_callback; 
    $request = $this->oAuthRequest($this->requestTokenURL(), 'GET', $parameters);
    $token = OAuthUtil::parse_parameters($request);
    $this->token = new OAuthConsumer($token['oauth_token'], $token['oauth_token_secret']);
    return $token;
  }