the basic way I do newfs on my system is...
1. format and partition the drive accordlingly using the format command.
#format <enter>
.. select which drive you will partition and format. it standard cases, select 0. (normal boot and system drive)
2. after you saved and format each of your partitions
3. goto the unix prompt a type newfs /dev/rdsk/c0t3d0s0
4. and option of -y, doesnt hurt saying yes to any prompts.
but makeyour you understand what your devices aliases are..
ie. c0t3d0s0, c-controller, t-arget, d-isk, s-lice.