The budget shall be the principal item of business at the first regular monthly meeting of the council in September and the council shall hold adjourned meetings from time to time until all the estimates have been considered. The meetings shall be so conducted as to give interested citizens a reasonable opportunity to be heard. The budget estimates shall be read in full and the city manager shall explain the various items thereof as fully as may be deemed necessary by the council. The annual budget finally agreed upon shall set forth in detail, the complete financial plan of the city for the ensuing fiscal year for the funds budgeted and shall be signed by the majority of the council when adopted. It shall indicate the sums to be raised and from what sources and the sums to be spent for what purposes according to Sec. 7.05. The total sum appropriated shall be less than the total estimated revenue by a safe margin. The council shall adopt the budget not later than the first week of October or at such date the law prescribes by resolution which shall set forth the total for each budgeted fund and each department with such segregation as to objects and purposes of expenditures as the council deems necessary for purposes of budget control. The council shall also adopt a resolution levying whatever taxes it considers necessary within statutory limits for the ensuing year, the sums fixed in the budget resolution shall be and become appropriated for the several purposes named in the budget resolution and no other.