Fiamma F80s installation

Hi, so I have just bought a F80s awning to fit on my Citroen relay conversion, the problem is there are 3brackets , small , medium and large. The instruction manual says the large bracket goes on the back of the van, but if you look at the fitting videos on line, they clearly show that the large bracket goes on the front?. i have had no luck getting any information for over a week now, contacted the place I bought it from  they I turn have asked Fiamma technical, but still waiting. Be grateful for any info.

Thanks

Brian