It's best to work in a well ventilated area otherwise the fumes will get to you.
Tape the image face down on to the fabric.
Soak the brush with a little bit of turpentine and brush it on to a small section of the image. Rub down on the area with something hard (such as the end of a paint brush) for a few minutes.
Paint more of the image with turpentine and repeat step 3 until you have covered the whole image.
When you have finished painting and rubbing the entire image take a peak under one of the corners. If the image is too faint repeat the previous steps until the print is dark enough.