the software that you need is the HDToolBox. normaly is in the install disk of workbench. the 3.0 wb came without an install disk at first but if you have one go and boot from it. if you have wb3.1 disks is even better. run the HDToolBox, it will ''see'' the hard disk, it will ask to install it, you have to say yes, and after that go to partition the disk. make a no more than 512mb boot partition and all the other partitions no more than 2gb. install the file FastFileSystem in the disk, you will find it in the directory L of the install3.0 or 3.1 disk. after all the setup, press save and reboot with the workbench disk in. format the boot partition and reboot with install disk to install the workbench :-)
wb3.0 and 3.1 can't see easy big disks and partitons without some patches that may you need in the future. for now go this way.
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if you don't have install disk use the tools that amigakit propose in a similar way. :-)