supermicro 2u hotswap hdd & ram install newbie question

i just get the supermicro 2u twin 6027TR-D71RF+ server and buy the hdd,cpu,ram separately

i have install it and found tohave long beep sound on starting, is this normal?

i have question as below, there is 12 hdd slot there.

3 x 2 in left, 3 x 2 in right

i would like to config raid 10 on left and config raid 1 on right

on left                                  on right

<hdd1><hdd2>                   <hdd5><hdd6>
<hdd3><hdd4>                   <empty><empty>
<empty><empty>               <empty><empty>

may i know i insert the hdd as above, is that correct?

if each cpu (4 cpu total) using only one dimm ok? (16gb)  or need at least 2 dimm per cpu