You'll need only one Admin server instance(you can migrate this any time)...
Weblogic should be installed in both machines.
1) Create domain in hardware 1
2) Create domain in hardware 2
3) Configure nodemanager in both hardwares.
4) Use nmEnroll from hardware 2 to propagate security to tomain in domain hosted in hardware 2.
5) start admin server in hardware 1
6) Configure 2 machines using admin server (1 for each hardware) and make sure you can connect from Admin console to nodemanager
7) Create a cluster using admin server.
8) Create servers using admin console and add to machine 1 or 2.
9) Start the servers from Admin console.
This is the most common way of doing it, but you may also use WLST scripts, you may also configure it all manuall without nodemanager and start managed servera manually, you may use a domain template builder.
Take a look at edocs.bea.com and look for Admin docs. You'll find all there in details.