To install Linux on a SPARC based computer, should be strightforward if you follow the informations provided by your distribution.
To boot from a floppy drive you have to have an install image on
a floppy disk and to issue the boot floppy from the
OpenBoot.
If your computer does not have a CDROM or a floppy drive, you can
always try to perform a network installation using
NFS as explained by this French document:
http://www.linux-france.org/article/materiel/sparc-install/Sparc-netinstall.html
. Basicaly, you have to set up an NFS server and to
boot your computer using the boot net vmlinux
nfsroot=192.168.52.12:/tmp in order to access the image
that is exported by the 192.168.52.12 computer on
the /tmp directory. Another source of information,
this one is written in English, is this FAQ from the UltraLinux
website ( http://www.ultralinux.org/faq.html#q_5_9
)