OpenWrt install on GL.inet GL-AR750s EXT (slate)

hello all!

has anyone ever installed to this particular device? I just received one and i'm new to openwrt (brand new.. as in this is my first install).
I don't care for the firmware that this came with.
There's a ton of back-and-forth about nands and nors, etc.. before I go ruining this, can anyone tell me which to download specifically and what i need to do to install it?