All details, including application instructions, are available in the USDA Wildlife Services Vacancy Announcement June 4-8 2018.
To apply for any of these positions, you must send your documents to the State Director for the specific state to which you are applying. See this list for names and addresses for each state (https://uofi.box.com/s/3o9pfgnrzds1607swe9jj8qo1i4c9uho).