Transportation is fully included in the trip, with a voyage via an expedition ship. Travel time can vary depending on weather conditions, but normally it takes approximately 2 days each way to cross the Drake Passage.
If you have more time, consider adding on a visit to Punta Arenas, Chile, which can be accessed via a short flight from Ushuaia. If you have less time, consider skipping the South Shetland Islands and heading straight to the Antarctic Peninsula. Be sure to pack for extreme weather conditions, with lots of warm layers and waterproof gear.