To log into CSC Digimail, you need to visit the official website of CSC and click on the Digimail option on the top menu. Once you click on it, you will be redirected to the Digimail login page. Here, you will need to enter your username and password, which you would have received while registering for the service. After entering the correct credentials, click on the 'Login' button to access your Digimail account.