A fantastic guide that's constantly updated can be found here: EAB and abime.net wiki project
WinUAE has the option of mounting and preparing a real hard drive for use on an Amiga! This option is only available in Win2k-XP. Win9x-ME unfortunately won't allow this feature.
Once mounted and formatted, the contents of the HDF can simply be copied directly over to the hard drive. Then it can be placed back into the Amiga ready for use. The WinUAE device name to use with HDtoolbox or similar utility is "uaehf.device". If you've already partitioned the drive Amiga side, it should be visible in the hard drives tab after using "Add Harddrive".
Read the WinUAE documentation for further details, or refer to the internet.
CrossDOS allows an Amiga to read PC formatted 720K disks. In order to use it, the files PC0: (1 disk drive) and PC1: (2 disk drives) must be copied from the "Storage/DosDrivers" drawer to the "Devs/DosDrivers" drawer on either your hard drive or bootable Workbench disk depending on which you use.
Also make sure "CrossDOSFileSystem" is present in the L directory. If not, there is a copy on the Extras disk.
Once installed, you will see an extra icon appear for any disk inserted into the drive. Use this icon to format floppy disks for use on a PC.
Download "Chunker.lha" (or similar program) from Aminet and split the required file into approx. 700K chunks. Then use the PC formatted floppies to copy over the smaller files onto your Amiga hard disk. Once all have been copied over, use "Dechunk" to join them back together and re-create the original file.
A serial cable and relevant software can be used to copy over files. One such program is "PC2Am308.lha" available from Aminet. I suggest placing the software on a bootable floppy disk. If the software is running within a Windows environment, be aware that Windows XP may have issues.
If problems do exist in Win XP other serial programs might work, such as hyperterminal (XP side) and ncomm (Amiga side). Aminet also has other solutions that may be applicable.
Finally, the Amigaforever package , as well as containing all the official ROMS the ClassicWB requires, also provides a useful tool called Amiga Explorer. This allows easy transfer of files over a serial cable and comes with full instructions and support from Cloanto.
PCMCIA flash cards or a PCMCIA->Compact Flash adaptor can be used for transferring files, again using the utility "Chunker.lha" from Aminet to split the file if required. While there, grab the packages "cfd.lha" and "fat95.lha" so your Amiga can communicate with the card.
You will of course also require an inexpensive card reader for your PC.
Make sure you get the correct hardware known to be compatible with the Amiga's slot as some people have reported problems with certain cards. Check out Amigakit for examples of packages available, or if you want to be sure that you obtain a solution that works.
PCMCIA network cards can be used for transferring files, but configuration can be a complicated affair. Read in forums and on the internet for further details. A list of compatible cards can be found on Aminet in the "3c589.lha" and "Cnetdevice.lha" archives. "Cardreset.lha" may also be required.
A TCP/IP stack for use with network cards is already included in the ClassicWB "MyFiles/Install" drawer.
The ClassicWB has the software PC2Amiga pre-configured for this method of transfer once it's installed. Again, the Aminet software "PC2Am308.lha" can be used on a bootable floppy to copy over files using this cable. If the software is running within a Windows environment, be aware that Windows XP may have issues.
You'll need to convert the "Real_Amiga_Install.ADF" back to an Amiga 3.5 disk. After using the transfer methods outlined above to get the file across to the Amiga, go to Aminet and pick up either "TSgui.lha", "Transadf.lha", "Image2disk.lha" or a similar utility. This will write the file back to an Amiga floppy ready for use.