Okay...
Your kick31.rom file is an image of a ROM that's built into every Amiga. It contains the core of the Amiga's operating system, but in order to boot the system you need a Workbench disk. You can find these on the internet, if you search for 'Workbench+adf' in Google for instance, something should come up. If possible, download the complete set of 6 disks:
Workbench, Extras, Locale, Fonts, Storage and Install
If you can't get all six, just the Workbench disk will do for minimal use.
Start up WinUAE and use UAE's Floppies tab to insert the Install disk into df0:. If you don't have the install disk, put the Workbench disk in there instead. Click Ok to start the Amiga and wait for it to boot. It should take about a minute.
When the Workbench screen appears, you should see a disk icon with the caption 'DH0:
?' below it. Click on this once and then use the right mouse button to choose 'Icons > Format Disk' from the menu bar at the top of the screen. Give the disk a name ('Boot' or something, it doesn't really matter) leave all the other options and choose 'Format'. Confirm this when you are asked and wait for the format to complete.
Now, if you have the full set of Workbench disks hit F12 and open the Floppies tab to insert the Extras, Locale, and Fonts disks into the empty floppy drives. Press Ok to go back to the Amiga, then open up the Install disk by double-clicking its icon and then double-click the 'Install' icon that should be there. During the install process, you will probably be asked for the other disks (it will say 'Please insert the volume 'Storage'' for example) and you will have to go back to the Floppies tab in UAE to swap disks.
If you only have a Workbench disk, and not the full set, once you've formatted the Amiga's hard drive, use the right mouse button to choose 'Workbench > Execute command' from the menu, and type:
copy df0:#? dh0: ALLThen wait for the files to finish transferring.
When you're complete, hit F12 and choose 'Reset Amiga' from UAE's Misc tab, eject all the floppy disk images from the Floppies tab, and then click Ok. The Amiga should then boot from the hard disk image... Fingers crossed ;-)