inherited a tank, fishless cycling now

Hi Nancy,
As long as the ammonia and nitrite readings are both at 0ppm, there is not much to worry about. Do not overfeed is more important than making sure of "eating enough". Fish do not need a lot of food to stay alive. Make sure there is no leftover in the water after feeding should be the priority.

You can add more fish one at a time every 2-3 weeks as long as the tank is not overstocked. Did you ask how to wash the filter? Just gently wash the filter media in a bucket of tank water or treated water should do the trick. Squeeze too hard might result in losing a lot of good bacteria.