Georgia DDS requires that all Drivers Ed courses must last exactly 30 hours. Aceable will not unlock the next module until the time has run out for that specific section.
Simply wait for the timer to run out. Once it does, the next section will unlock on its own.
The "full course" option is if you do not want to continue the course. If you choose this option, it may hinder your ability to receive a certificate of completion, which is a Joshua's Law requirement.