How do I put the i-cuff on my camera?

Leave the stock rubber eyecup on. Next, set your diopter, then push the rubber elliptical eyecup forward; (taking it off would result in the diopter falling out on most cameras and allow dust to enter the viewfinder). Then, inserting two fingers on either side of the cuff to widen the elastic, pull the i-cuff over the viewfinder. Lastly, tighten down the velcro strap after positioning it forward or backwards making a comfortable fit to your face. You will also find it helpful to adjust the x and y axis of your viewfinder brackets.

For shooting overhead, under arm, or down low, try rotating the i-cuff 45 degrees counter clockwise, allowing it to shade the viewfinder when away from your face.

And in terms of cleanliness and health safety, i-cuff may be lightly washed with Woolite or other hypoallergenic soap and hung to dry.