Store Identifier ID in cookies when the visitor reach our landing page

[Joey]

When the visitor reach our landing page, the identifier is included.

e.g. https://www.domain.com/?identifierid=12345

‘rdentifierid=12345’ is the click identifier. The value represents which affiliate it is from.

 

Now I need to store these values in our server server (may be cookies), so that this value can be used throughout the period the user browsing the website. When user checkout, I will send the following links through the order confirmation page.

Source: http://track.clickwise.net/pb?TotalCost=100&identifierid={$identifierid}

Results send to: http://track.clickwise.net/pb?TotalCost=100&identifierid=12345

 

So how can I store this identifierid in cookies and which files I should added the code? 

Thanks!