OS 1.x doesn't come with a harddisk installer, but if you aquire a harddrive there's software there to help you install.
Fx. GVP HD8(+) have the FaaastPrep diskette which helps you to partition and format the harddrive, and install the Amiga OS.
If you already have a formatted harddrive which is accessible to the system, all you have to do is do a filecopy from the Workbench diskette to the Harddrive.
You can copy files using the CLI copy command
copy df0: hd0:
Some things you might need to be aware of is that the harddrive needs to be bootable. which requires a firmware from a controller or in the kickstart rom, and the harddrive's bootable flag is set.