Newbie- Spoiler board..Did I miss a Guide?

Hi All!,

So I have now built my z1 1500x1500. Great guides- very easy to follow. Only hit three snags- Tensioning (no idea how to go bout that- tried and just seems to muck everythign up. So any guidence on that would be great, One of the Y axis leads is a tad tight and the screw for the Z axis is too long for the spacer for a Mafel. Machine looks amazing and cant wait to get started.

So.... spolier board... Any guidence on making one and installing one? As I may be being daft but cant see a guide and from reading it seems this is kinda important part of the build.