Before you step on the fuse, you should be able to map out the path it should take. It might help to print out a screen shot and draw your plan on it.
Suppose you have a fuse burning in a northward direction. It will burn across all force arrows pointing N, NE, E, NW, and W. It will stop burning if it encounters a force arrow pointing against it in the S, SE, or SW directions.
Ah, but you have those arrow turners. The blue one rotates the arrows 1/8 turn clockwise so that a SW pointing arrow will point W and the fuse can burn across it. The red one rotates the arrows 1/8 turn counterclockwise so that a SE pointing arrow will point E and the fuse can burn across it. (Notice that the red turner becomes blue after you've used it and the blue turner becomes red, so you can't keep turning in the same direction.)
Because of those turners, the only arrow that absolutely stops a N burning fuse is a S pointing arrow. A W burning fuse is stopped by an E pointing arrow, and an E burning fuse is stopped by a W pointing arrow.
Et cetera.
Now you should be ready to draw your map onto the screenshot. Look at the first place where the fuse splits. It has a choice of:
E
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×but will be stopped by a W arrow
N
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×but will be stopped by a S arrow
W
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×it will go across the SE arrow if you use the blue turner to make the arrow point S)
So it goes W.
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×Next intersection: the fuse will burn north. Can you see why it will be stopped in the west direction?
Look at the arrows on your screenshot, and keep planning the fuse's burning path using this kind of reasoning. Once you've got your map, all you'll need to do is light the fuse and step on the correct turners at the correct times.