well, I'm guessing that you've installed an ide disk and you've only got two hard disks. I don't know if BSD can handle more than two since the documentation says one thing and the illustrations seem to show more than two hard drives. I've only used /stand/sysinstall to do a post install configuration but you can do it manually. From there you can choose the disk slice editor or fdisk. If you haven't formatted the drive with a Microsoft partition you should be able to create a slice from here. I used a Microsoft partition to dual boot Windows 2000 and freeBSD so I had to delete the .
After the selection of options you will be finished with the editor, you quit and return to the previous menu and label the drive. I'm a newbie so I chose auto defaults for my drive. Once you have done this you can choose no to the prompt about future compatibility or yes if you might use a different boot manager at a later date. I chose no. I use the BSD boot manager. YOu will choose a swap partition, a name for the file mount point like /something and choose yes to commit the changes. The file system will be made by sysinstall. Don't interupt the process and be ready to wait quite a while depending on the size of the drive.
You may be able to skip the format bit and go straight to the disk label program.
To do this manually requires the heads, cylinders and sectors. Then the labeling and partitions are manually set by the number of sectors per cylinder. Lets not get into that unless we have to.
Good luck,
BJ Corne