How to add/mount SATA on Pogo series 4

[ibexmonj]

Hi all

I have used a USB flash drive of 8GB to install ARCH and boot with it.

Now I have inserted the SATA hdd on the top

I do see it if I use the following
fdsik -l

but I cant see it if I use
df command

Can anyone help me with how I should mount this HDD and how will the system know when to save to flash and when to save to this HDD ? please advise