crypt puzzle ,I have blue and green flowing throgh and lighting up but red and how to reach valves or complete puzzle has me stumped ,any ideas ?

Red has you using blood on the grates.

You can use your allies, slashing at them to make them bleed on to it.
You can use blood rain on to the grates.
You can use bloated corpse on the bodies around the room and explode them on to the grates.

Once enough blood has seeped down, you can bless it to activate the trail.

If the path downstairs is set correctly, you have solved the puzzle and you can move on.

And example is here, on youtube:
https://www.youtube.com/watch?v=Z-N6VVD-5t8

be jiggered , d'accord !