Once you have your CSLab unix account set up, you can get a VPN account (with the same user name but a different password) from "self-serve VPN account registration" at https://csweb.cs.toronto.edu/vpn.html
To configure the VPN, the short version is that it's an L2TP type connection, hostname l2tpipsec.cs.toronto.edu, and you can find the "pre-shared key" at https://csweb.cs.toronto.edu/l2tp-front.html
For MS Windows 10, the long version is at https://support.cs.toronto.edu/network/win10_l2tp.html
For Mac OS X, you should be able to follow the user-friendly Mac interface in most respects, but note that you need to check the box which says "Send all traffic over VPN connection". You'll find this under "Advanced". (Otherwise it tries to send stuff heading to CS through the VPN connection and send everything else directly, which makes sense except for the fact that its algorithm for determining what to send over the VPN connection actually results in everything going directly, so the VPN has no effect.)
Note that changing networks (e.g. closing your laptop and going home and reopening it at home) disrupts the VPN connection, so if you are connected to the VPN and then change networks, you will find that you don't have any network access at all (unless your VPN software is clever enough to notice that the connection is dropped and exit by itself). That is to say, from now on in the case of network problems, you need to remember to consider the possibility that you have a non-functioning VPN connection. In such a situation, simply disconnect the VPN and your network access should start working again.