hp smart array p410i controller firmware

I'm new so im trying to get a real understanding for this, so all advice and education is welcome and very much appreciated. Side note, can someone explain to me what a RAID key is and how do i find it or get it so i can back it up properly in case i need it in the future.? would it be under manage license in the RAID config menu? I found another thread on here that says they used sas2flash to get the job done. I am also understanding i would need to flash whatever controller card i get in order for it to work properly? if so, can someone point me in the right direction for the firmware i would need to flash maybe w/ a tutorial? im assuming i hook the sas expander directly to the controller once everything is setup and the drives to the internal ports on the sas expander and the array to the external ports on the controller. is this true because others are using LSI HBA to get the job done? i would think either way i need the sas expander for my situation. People are saying go w/the H220/240 and a SAS expander to get the best performance and is the best solution.

i do however have 2 backplanes 8drives on each for a total 16 on the server itself i'd like to make use of, so i'm currently dealing with this JBOD issue in order to have Unraid do what its supposed to do. i will have all my data on the array and then hook it to the server. i'm also new to building servers as i'm coming from desktop environment. i have the D元80 G7 with its disc storage array partner that i want to hook up.

Hp smart array p410i controller firmware