Review this guide here to use ACU or ORCA to configure the array. http://h10032.www1.hp.com/ctg/Manual/c02289065.pdf
Regarding your question of "What is the best RAID I could use" it's sort of like asking "What's the best car for me?". Without further details, we can't provide a lot of valuable information. How many drives do you have? What are your performance requirements? What is your tolerance for data loss? What is your capacity requirement? What controller is in your server?
On average, and making some basic assumptions; if you have more than two drives then you'll probably want to create a single RAID5 array. If you have lots of disks in the server, mark one as a hot spare so it can take over in the event of a failed drive. RAID6 provides better prevention against data loss but comes with a write performance, and capacity, penalty. You'll also likely need the "Smart Array Advanced Pack or SAAP license" on that model server in order to do RAID6.