A bloke on this forum has the instructions, and will email them to you apprently
Thought I had some for its big brother the Royal 5, but was wrong.
It is really easy to work out, but get some coloured tape first. You should have five poles. One ridge pole, and four spike poles. Trying to remember but think three of the spike poles same hight, and one taller. The three short ones are for the back, and front. The tall one is for the middle.
Peg out the inner tent.
One of the short spiked poles goes into the tent, and out though the hole at the back. The tall one goes out though the hole at the front of the inner tent. Slid the ridge though the loop in the middle of the inner, and the spikes though the holes at either end of the ridge pole. There maybe in the bag little bits of black plastic, these go on the spikes before the ridge pole.
Then the flysheet goes on peg it out, and use the other two poles to hold the front up.
There may also be white discs of plastic these slid over the spikes when the fly is on. Some sort of rain stopping feature.
Some of this may not make any sense because there were a lot of different version of the challenger series. At least four, maybe five for the five.
Just as a point, only advantage you might have in weather with one of these, is you could storm lash it. Domes seem to be the best at weather.
If none of that helps you could get in touch with Lichfield, they used to be a really good bunch of people. My sister worked there, and my combat one(first tent) is in the loft still.