We have the same one in the gym. Itīs easy..place one end of the olympic bar into the adapter, fix the grip-adapter at the other end of the bar, and load on weights...
which kind of plates 45 or 35 i use depends on in which fashion i will do the movement (more bend over = 35īs, or a bit more upright = 45īs). But honestly, i saw so many guys in my gym which are doing the t-bar row just standing compl. upright.