Section 3. The order shall contain an estimate of all damages sustained by every person in his property by reason of such taking as of the date of the adoption of the order, and shall contain an estimate of the cost of the improvement, including such damages, and, if betterments are to be assessed, a description sufficiently accurate for identification of the area which it is expected will receive benefit or advantage, other than the general advantage to the community, from such improvement, and shall refer to a plan of such area, and shall contain an estimate of the betterments that will be assessed upon each parcel of land within such area. Notice of the adoption of such order shall be sent forthwith by registered mail to every person, whose address is known, appearing of record to have an interest in any land to be taken, damaged or assessed, by or on account of the proposed improvement, setting forth all estimates contained in said order in relation to said land, and a like notice shall be posted in a conspicuous place on each parcel thereof. Such order, plan and estimate shall be recorded, within ten days from the adoption of the order, in the registry of deeds of every county or district in which property to be taken or assessed is situated.