Right so which end of the drain do you guys start cleaning from?
Welcome to the forum. Are you referring to a clogged pipe or tile, or are you asking about building a ditch? If possible I like to do pipe or tile from the bottom end, so anything you break loose doesn’t make the plug worse. If a ditch that has a little water, sometimes I go from top down to make sure I have slope, but sometimes that’ll get me too much water where I am digging, so then I’d dig from end back upstream, so water can leave once it’s passed me. Others probably have there own preference.
Cleaning? Like cleaning with a jetter? If we are laying pipe always start at the lowest point and work up. Just don't do this-