It's very easy to follow the direction with the help of a kitchen timer. I rinse under running water (mine is filtered), soak in soapy water then rinse in filtered water. After 2-3 nebs, after washing the pieces go in a pan of distilled water over a very low flame, and I set the timer for 10 minutes (about the time it takes my small saucepan to boil.) When it rings I check to be sure it is boiling, set the timer for 5 more minutes then turn off the burner when it rings and let it cool. I remove the pieces and dry on a clean paper towel. I save the distilled water (covered) to use 2 more times. My kitchen is in the center of my house, and is also my office, so I do the boiling when I will be nearby or while cooking. I use a round silicon trivet in the bottom of my pan to make sure the parts don't rest on hot metal, but I'm not sure it is necessary.
I not only love the speed of it, but am coming to love the very fine mist - it seems to act pretty fast.

@lilianna An alternative way to sterilize as I also own the eRapid. I soak in hot tap water with a drop of dawn for a few minutes to 20 minutes, rinse under running hot tap water (our water heater is set to 135+). Every few days after cleaning I pop in†o Bololo baby bottle sterilizer with distilled water in basin. It steam sterilizes for about 13 minutes.

The only issue I have had was when our hot water started to go and produced rusty water. In the beginning it was only slightly rusty but I did not catch it. After soaking and steaming the eRapid it was evident I needed to replace it because it was not operating properly. It was time to replace anyway, but I think the rusty water hastened its demise.