Transferring software and files from PowerPC G3 to PowerMac G4

I would like to transfer the 4 accounts (family of 4 each with our own accounts established 9 years ago and updated periodically) with programs and files from a iMac model PowerMac 2.1 with CPU PowerPC 750 400 mHz Power PC G3 using OSX10.4.11 to a newly acquired used PowerPC G4 PowerMac G4 2.1 Dual 867 mHz using OX 10.2.  The google search told me the steps of connecting the system via Ethernet, turn on file sharing on the iMac, mount the iMac's file system on the Power mac. Copy your files.
I connected the two system together using an ethernet cable. Then I when to the imac system preference, sharing , internet tab and checked on Built-in Ethernet.  I did the same for the powermac.  I was lost at the step of ''mount the iMac's file system on the powermac.''  I do not know where to look or saw the word ''mount'' anywhere.