Yes, the Seattle ferry terminal is generally easy to navigate. There are signs throughout the terminal to help guide you to your desired ferry and there are typically staff members available to answer any questions you may have. I suggest arriving at least 30 minutes before your scheduled ferry departure time to allow time for parking, ticketing, and boarding (if you are walking on). If you're driving, the lines can be a little stressful with Seattleites using it for their commute (and sometimes they are grouchy when tourists don't follow the rules).