The top four at each subdistrict qualify for districts. The top 4 from each district tournament qualify for state. With 4 districts, that means 16 from each weight qualify for state.
There may possibly be more qualify for districts from your sub district if the other subdistrict does not have 4 competitors at that weight.
For example if you are in 2 North and 2 South only has 3 wrestlers at that weight, then the top 5 from 2 North will qualify for districts.