When looking to take advantage of military tuition assistance, the first step is always to connect with your education service officer (ESO) from your branch of service and get approval from your command. They will have updated information on the process for your specific branch of service.
The Coast Guard tuition assistance program is designed to assist Coast Guard personnel in broadening academic or technical backgrounds by providing funding for off-duty independent education. Specific policy and guidelines are outlined in ACN 112/20 - SEP 2020 FY21 COAST GUARD TUITION ASSISTANCE (TA) POLICY
More information can be found at: Coast Guard Tuition Assistance Link
You can submit TA Applications up to 90 days from the class start date, NLT than 14 days prior to the course start date.