1.3 and below came with neither an install disk, nor a disk prep utility. Simply copy the contents of the disk to your HD and reboot. Assuming of course, your HD is formatted, partitioned, is small enough to be seen by the OS, etc. :lol:
...I'm guessing your HD is somewhat prepped though, which is why it boots to the command prompt. When booting off the Workbench floppy, you might see an icon that represents your HD and partitions. If the icon reads something to the effect of "bad" or has garbage and goofy text under it, go ahead highlight it and select 'format' to prep it. If you do not see icons for your HD, you can always use an A2091 install disk to prep your HD using OS1.3.