Setting up a supermicro 826 with a X9DRi-LN4F+ motherboard

I just picked up a Supermicro 826 with trays but no drives. It will hold 12. I put 10 drives in it, turned it on and was able to get into the system settings so that much is OK. The motherboard is an X9DRi-LN4F+ I was told it was running before I bought it. I am self taught, though i passed the Microsoft server and workstation exams for Server 2003 as well as the TCP/IP. This was 20 years ago and haven’t used it since other than at home. I like to say I know enough to be dangerous. I would like to install TrueNAS on it and use it as a home NAS with web access. to replace two Western Digital units with 2 - 4T mirrored drives in each and a Buffalo TerraStation with 4 - 2T drives running raid 5. My question is where to I begin. Do I need to install the base system from SuperMicro and then TrueNAS or will TrueNAS be all I need. Really just looking for someone to point me in the right direction so I’m not going off in the wrong direction. tia