SP initiated flow

[ajender210282]

Hello all,
I am new in SAML. So can anyone help me to integrate this.
Case is:

1. User login in my website (Stored in my DB).
2. After login they get a link (WRKIT LINK) on the dashboard.
   WRKIT guys provide me SP.xml. I don't want my user to login on another third party site due to security reason.

I am try to work as https://github.com/auth0/node-samlp
but I am confused. From where I should call bellow code and what parms I should pass here.
app.get('/samlp', samlp.auth({
issuer: 'the-issuer',
cert: fs.readFileSync(path.join(__dirname, 'some-cert.pem')),
key: fs.readFileSync(path.join(__dirname, 'some-cert.key')),
getPostURL: function (wtrealm, wreply, req, callback) {
return callback( null, 'http://someurl.com')
}
}));

same as :
app.get('/samlp/FederationMetadata/2007-06/FederationMetadata.xml', samlp.metadata({
issuer: 'the-issuer',
cert: fs.readFileSync(path.join(__dirname, 'some-cert.pem')),
}));