The reboot should take you back to OpenBIOS. Boot from the CD again but this time into the installer:
Time to install! For the most part, the defaults are fine, but there are a few places where you'll want to make changes.
When you reach the networking options, pick a hostname and check Yes for Networked. Use 10.0.2.15 for the IP address, QEMU has its own internal network.
Name service: Other
Part of a subnet: No
Now set the time zone, time, and date. When you get to "Allocate Client Services" just click Continue. Pick an additional language if you'd like one.
Choose how much you want to install. End User is enough to run it, Developer will let you build things, and Entire Distribution will just install everything. If you really want to, you can Customize the installation but it's easy to break things so it's best to stick with the available software groups.
It should auto-select the available disk for you but if not you can select it and click the right arrow to add it to the selected disks.
When it asks about preserving data you can click continue. Click Auto Layout and continue, the defaults are fine. Click continue on the remote file systems page.
Now you can review the last few options. If it looks good click Begin Installation.
Make sure you choose Manual Reboot when prompted - we need to change some settings or else it won't boot.
Once everything is finished you should see "The finish script log `finish log` is located in /var/sadm/system/logs after reboot." followed by a root prompt (#).