First get the ISO. This is not straightforward, as the developers do not release an official ISO for download.
http://openbsd.berkeley.edu/pub/OpenBSD/4.4/i386/install44.iso
http://anga.funkfeuer.at/ftp/pub/OpenBSD/4.4/i386/install44.iso
http://www.cyberciti.biz/tips/download-openbsd-4-cd-iso-images.html
On the box, you need TWO network cards. One connected to the work, the other connected to the LAN
If you would like remote administration via SSH, a third network card is necessary.
The following is taken from
http://www.openbsd.org/faq/faq4.html#Install
and excludes all the explanation. See also
http://www.openbsd101.com/installation.html
It's easiest to do everything in one session. If you mis-type, reboot and start over.
boot> Enter
(I)nstall, (U)pgrade or (S)hell? i
Terminal type: [vt220] Enter
kbd(8) mapping? ('L' for list) [none] Enter
Proceed with install? [no] y
Which one is the root disk? (or done) [wd0] Enter
Do you want to use *all* of wd0 for OpenBSD? [no] y
> p m
> a a
offset: [3148740] Enter
size: [35953470] 500m
Rounding to cylinder: 321300
FS type: [4.2BSD] Enter
mount point: [none] /
> a b
offset: [3470040] Enter
size: [35632170] 600m
Rounding to cylinder: 626535
FS type: [swap] Enter
> a d
offset: [4096575] Enter
size: [35005635] 300m
Rounding to cylinder: 257040
FS type: [4.2BSD] Enter
mount point: [none] /tmp
> a e
offset: [4353615] Enter
size: [34748595] 200m
Rounding to cylinder: 176715
FS type: [4.2BSD] Enter
mount point: [none] /var
> a g
offset: [4530330] Enter
size: [34571880] 8g
Rounding to cylinder: 12594960
FS type: [4.2BSD] Enter
mount point: [none] /usr
> a h
offset: [17125290] Enter
size: [21976920] 6g
Rounding to nearest cylinder: 8401995
FS type: [4.2BSD] Enter
mount point: [none] /home
> p m
OpenBSD area: 1537.5M-19092.9M; size: 17555.4M; free: 6628.4M
# size offset fstype [fsize bsize cpg]
a: 156.9M 1537.5M 4.2BSD 2048 16384 1 # /
b: 305.9M 1694.4M swap
c: 19092.9M 0.0M unused 0 0
d: 125.5M 2000.3M 4.2BSD 2048 16384 1 # /tmp
e: 86.3M 2125.8M 4.2BSD 2048 16384 1 # /var
g: 6149.9M 2212.1M 4.2BSD 2048 16384 1 # /usr
h: 4102.5M 8362.0M 4.2BSD 2048 16384 1 # /home
i: 1537.4M 0.0M MSDOS
> q
Write new label?: [y] Enter
Mount point for wd0d (131584 KBytes)? (or 'none' or 'done') [/tmp] Enter
Mount point for wd0e (90624 KBytes)? (or 'none' or 'done') [/var] Enter
Mount point for wd0g (6656 MBytes)? (or 'none' or 'done') [/usr] Enter
Mount point for wd0h (4096 MBytes)? (or 'none' or 'done') [/home] Enter
Mount point for wd0d (131584 KBytes)? (or 'none' or 'done') [/tmp] done
Are you really sure that you're ready to proceed? [no] y
System hostname (short form, e.g. 'foo'): puffy
Configure the network? [yes] Enter