SSH is not really wht you want to use in this case. Quite simply, ssh is used to access the terminal remotely, so you can use unix commands to control the machine. Not really something meant for the average user.
What you need, I'd assume, is access to your files and/or remote control of your computer. To access your files you need to use FTP, and for remote control you'd want to use VNC.
FTP: To turn on FTP on the Mac go to Apple Menu --> system preferences --> Sharing and tick the FTP box.
If you are using a router (including wireless routers such as Airport) on the Mac that is sharing its files, you may need to setup something called "port forwarding". This basically tells the router that anything coming in asking for an FTP connection should be sent to your specific Mac. If this is the case, just let us know what router you're using and we'll point you in the right direction.
Next, you need to work out what address your server is running on. This is usually an IP address, and looks something like 12.65.23.228
If you're plugged straight into the Internet without any router or wireless, then this will appear in the System Preferences --> Network under "TCPIP Address"
If you're using a router, you may need to check the setup for that to find the IP address.
From the client computer (ie: the one at work) you'l need to use an FTP client, of which there are lots of programs available many of them free. You'll then open a connection to the IP address you found before, and logon using your shortname (you can get this in System Preferences --> Accounts) and password.
VNC is a very similar arrangement, however you'll need to install a VNC server (or use the VNC option in the Apple Remote Desktop sharing) and a VNC client. It also works by IP address, though some VNC clients use a seperate password to your account password, so you'll need to set the password on the VNC server software.
