Go to
https://www.freefilesync.org/download.php
and don't click on the "start download" button at the top which is actually an advertisement, but scroll down to "Download FreeFileSync 11.0 Windows" or similar. And also avoid this advertisement if it appears next to the real download buttons! Click on something quite like "Download FreeFileSync 11.0 Windows".

You can leave the default selections on the initial page of the installer, but be sure to uncheck the box for the crapware on the next page.

Run FreeFileSync, and press the large green gear symbol towards the top right to change the synchronization settings. Change it from "two way" (not what you want) to "mirror" (this will do a backup).
You can leave the other settings at the default. (So press 'ok'.)

Now, you want to set it up with your local disk in the left panel (which is actually in more like the middle of the window), and the remote disk under your CSLab home directory in the right panel. It's easier to do this by typing than by using the file browser.

In the right panel, type "\\smb.cs.toronto.edu\username\backup" (without the quotes, of course), using your CSLab username in place of "username". Note the double-backslash at the beginning versus single backslashes elsewhere, and note that they are backslashes rather than slashes.

When you press return, it will do this silly "searching for folder" thing for a couple dozen seconds, and then perhaps actually give an error that it wasn't found, but just wait and it will give you the opportunity to "enter network password" which means to type your CSLab user name and password. After you do this successfully, you can press 'retry'. Then it will tell you that the folder \\smb.cs.toronto.edu\username\backup doesn't exist, but if you press 'ignore' it will create it. This is good, so press 'ignore'.

In the left panel, type something like "c:\users\yourname", specifying the directory of interest for backing up. Please ask me about space concerns before backing up a total of more than about a dozen gigabytes.

It will then start scanning that portion of your disk. Depending on the size of the source directory, this might take a while. (Which is why I had you type the bit in the right panel first.)

When it completes, you can press the 'synchronize' button at the top right of the window, which should say "mirror" in smaller letters as an indication of what it's going to do. And it's crucial that the arrow next to the mirror is pointing in the direction you want to copy... please verify this.

Then, you might be surprised at the amount of time it says it will take to do the copy. Subsequent copies will be much faster because it will only copy the changes, which is the whole point of using this software.

In fact, depending on what you're backing up, the amount of time it says it will take may well be longer than you have to spare at the moment. This is ok; do your other work while leaving it running for as long as you can, and then press 'stop'; when you start it again the next day it will pick up where it left off.

After the first completed backup, unless you have changed many large files you should be able to do the backup feasibly from wireless or from home (you'll need to connect to the VPN to be able to access smb.cs.toronto.edu from outside the department).

If you are backing up some subdirectory of \users\yourname, I suggest using a compatible path name in FreeFileSync so that you can easily switch to backing up a larger area in future. For example, I would back up c:\users\flaps\src to \\smb.cs.toronto.edu\flaps\backup\src or maybe even \\smb.cs.toronto.edu\flaps\backup\users\flaps\src