Network scan is a purchasable upgrade, so if it isn't there, you didn't buy it.
If you want to buy it through Xerox, you would need to order this:
497K08300 = FULL NETWORK SCANNING KIT
If you had it, it would appear just as those directions state
So you go to CWIS > Scan and create a folder on the machine
Then to Fax receive options, select the line and point it at the number of the folder you created (In my case Folder 2)
And if you have network scan, you should be able to now modify the folder here to send to an SMB share by selecting the folder and Change Settings
Then File Transfer settings
And when you select the option and then Next you would get to enter the network location you have.
In all honesty though, the price of the scan kit is likely much more than a small fax machine that would already have this feature built in. But if you do get one, this is the best setup instructions for it you are likely to find.