When a subdrainage district has been established as hereinbefore provided, the county drainage commissioners shall be the commissioners of said subdrainage district; and proceedings to organize subdrainage districts and to do improvements therein shall conform substantially to the provision of this chapter with reference to the organization, doing the improvements, and operating other drainage districts authorized by this chapter. Said commissioners are empowered and authorized to issue bonds of such subdrainage districts, and such bonds shall be so designated. The same proceedings, or as near as practicable the same, shall be had in the issuance of bonds of a subdrainage district as are required in the issuance of bonds of the drainage district in the first instance, as provided in this chapter. The proceeds from the sale of bonds of a subdrainage district shall be applied and used exclusively for doing the work within or for the exclusive benefit of said subdrainage district for the construction of internal drains of said subdrainage district, and in carrying out and perfecting its internal drains.