How to only use gmail for a NUS student to deal with emails

1. For NUS email account

1.1 Go to:
https://exchange.nus.edu.sg/
1.2 Then click the "Email Redirection" link, fill your gmail address in the following page. If you want to keep a copy of the email in my NUS mailbox, you may select the "Keep a copy of the email in my original mailbox.".

2. For SoC of NUS email account

2.1 Go to:
https://mysoc.nus.edu.sg/~myacct/mymaildest.cgi
2.2 Then add your gmail address to "My Mail Destinations"

3. Using your gmail account as your other accounts
You can use your gmail to send emails using your other email account name as sender.
This can be found in your gmail's "Settings->Accounts->Send mail as:", and please do select "Reply from the same address to which the message was sent".