According to this:
https://www.evga.com/products/product.aspx?pn=110-BQ-0850-V1
you should have 3x 8 pin and 3 x 6pin. Use 2x 8 pin even if the 2 extra 6 pin hang (daisy chain)
From what I understand from the site of EVGA, the PCIE cable is fixed on the PSU and that has 8 (6+2) pin and a 6pin. You use that 8 (6+2) pin and plug it to the GPU. Then you take one VGA cable, you plug one end to the PSU where it says VGA2 or VGA3 and one end to the second spot of your PSU. That should be all.
Indeed, I am gonna edit it now! Thanks!Minor correction: second spot of your GPU