I haven't tried a Mandrake network installation, but with a SuSE network installation, the procedure was to download about a 20Mb iso that was used to boot up and commence the network installation process. This was the process that I followed on my IBM X series notebook with a SuSE network install. I have an external CDROM connected via USB:
1. Download the SuSE boot-up iso 20Mb.
2. Burn the iso onto a cdrom.
3. Start the notebook and in the first few seconds press f12 to use the bios software to boot via cdrom.
4. The cdrom loads up the program to commence network installation.
5. Enter the ftp number ie 126.96.36.199
6. Enter the directory path ie /pub/suse/i386/8.1
7. Installation is underway!
For just a standard install with the Mandrake discs, the procedure is:
1. Turn on computer and press F12 for boot options
2. Select boot from cdrom
3. Installation is underway.
Looks like you need the pcmcia file on a floppy to get your cdrom working, then on your cdrom you will need the iso to start-up your network install.