Yeah,well if you'da asked how deep they till it woulda been alot easier.
Put your skids shoes about all the way up. First pass you might go 2-4 inches,second pass,you might be down to 6 inches,third pass you should be at about 8 inches,depending on your dirt,might need another pass.
And adjust that slip clutch like book says,and fill it full of gear oil and grease it.well not full of gear oil,what the book says,mine came empty.