The fax cable plugs into the back right of the machine towards the bottom. The machine has wheels and should be easy to move - you might have to push up the wheel release to get it to move easier.
The WC7435 has a knowledge base which is a great source of how to and problem solving solutions. Click on the link below to access the knowledge base and search on "fax line." You should get a search result solution for how to connect the machine to a fax line.
Post back and let us know if this helps.
I would like to set up our workcenter to fax, but have no idea where to plug in the fax line. It is pushed back against the wall already to I cannot see well to find a plug in. ideas?