Need some advice

[EvoStick]

I need some advice on this as I'm looking to build a gaming PC
The graphics card my friend is selling me his one (GTX 970) nothing special but it does what it's job is
My budget is basically £700-800, he's hopefully going to get an i5/i7 from the members market here second hand, but if anyone has any ideas basically on spec for the likes of Battlefield 1, No Man Sky etc
Thank you

 

[EvoStick]

I can get a copy of Windows and with the overclocking, I probably will at some stage if it's possible with what I end up getting, the case I've already picked just need to know what sort of Motherboard, Ram etc to go for, and also what sort of processor would best match