I bought this to restore the colour to two faded shirts, one a pale turquoise linen and the other a deep turquoise cotton, and also to dye an old towel which had become a somewhat dirty white colour. The dye was easy to use: I poured the liquid directly into the drum rather than the detergent tray as recommended, because this was easier to clean. I added the recommended amount of salt. I also put a water softening tablet in the detergent tray, as I have very hard water where I live. I put Aybel fixative in the fabric softener tray. My washing machine has a "hygeine plus" cycle, which holds the temperature at 60 degrees for 3 hours (or a lower temperature if you prefer) and I used this, together with an extra rinse cycle. Following that I put it through the normal cotton wash cycle with detergent.
The results were very good, with a rich and even colour. The darker shirt ended up with a darker colour, but both were fairly similar to what they had been when new. The towel looks new, too, and is a lovely medium turquoise colour.
I also tried dyeing a brown checked shirt that I had never liked. This was less successful, and I think in retrospect yellow or green might have been better.