The appraisers shall ascertain as nearly as may be the actual cost of construction of the ditch or ditches, drain or drains, together with all costs relating thereto, including the costs of the surveyor and engineer and the costs of appraisement and advertising, and shall ascertain to the best of their judgment the amount of the benefits which will accrue to each tract of land to be benefited thereby, and shall appraise and determine the amount of damage sustained by each landowner whose premises may be crossed by the proposed ditch or drain and award the same, and shall assess to each tract of land benefited by the construction of such improvements, its proportionate share of the costs of the right-of-way thereof, the costs of construction and other expenses above mentioned. They shall thereupon make and file with the county clerk a full and complete report of their acts and doings in the premises, together with the releases obtained from the property owners along the right-of-way of the proposed ditch or drain, and a statement of the amount or amounts to be paid for such release or releases. They shall also file an assessment roll therewith in which shall appear in proper columns the names of the owners, if known, and if unknown so stated, a description of the premises affected, the number of acres in each tract of land so affected and the value thereof, and if damages are allowed, the amount of the same, and if benefits are assessed the amount thereof.