Check out the "quick start guide" for your machine
I googled for "505 quick start guide" if the link I've pasted in here disappears:
http://publib.boulder.ibm.com/infoce...sa41516503.pdf
Buried in the back are instructions on how to connect to your machine via the HMC1 port and access the Integrated Virtualization Manager.
I've used this procedure to get into one of our p55A servers after it gave up searching for our HMC on the network
I didn't go hunting for lpar configuration stuff in here, but based on previous posts it looks like there should be something for you once you get here.
Interesting comment from Ross regarding licensing. I remember opting for something along these lines when configuring the system now I think about it...
I'll assume you have enough physical adapters to run multiple partitions...
A rule of thumb is that each Lpar needs it's own adapter slot or ownership of an internal adapter. You can't share ports on one adapter between lpars for example. There are exceptions to this rule (vio) with some extra work and resources.