Dying fabric in an automatic washer is best done in either a top loader or twin tub, best with a SS or porcelian tub as plastic may discolour.
Basically fills the machine with the desired amount of water, adds the packet of dye, allows machine to agitage for awhile to completly mix the dye with water, then add laundry and proceed with the cycle. One needs to stop the machine now and then to see if item(s) have taken the correct shade of color. Once this is done the machine can go on to spinning and rinsing.
If one does not have a top loader, you can dye items in any large basin or even bath tub. Wring out when the desired shade is reached, put in washer and set for "rinse and spin". Probably would be a good idea to let the washer to run empty on another rinse and spin cycle to make sure no traces of dye are still in the machine to foul any future wash loads.
Launderess