When the working sections are let, as hereinbefore provided, and the costs and expenses of location and construction, and all compensation and damages are ascertained, the county board shall meet and determine at what time and in what number of assessments it will require the same to be paid. The board shall order that the assessments as made by it shall be placed on the duplicate tax list against the lots and lands so assessed.
Neb. Rev. Stat. §§ 31-121