I am flying into Amsterdam airport and meeting my RS tour in Ghent the next day. How do I get from the airport to Ghent?
Take the train. From the airport, you can either take the fast (premium priced) Thalys to Antwerp and change to an IC train to Ghent, 2 hours. Or take the ICD train to Rotterdam, then IC trains to Antwerp and Ghent, 3 hours.
These trains at about the same time around half past the hour.
Or take the train into Amsterdam and spend the night, then get the Thalys to Ghent the next morning. That way, you could buy an advance purchase, non-refundable discount ticket for the Thalys, and see Amsterdam in the evening before heading to Ghent.
Use the website of the Belgian railways for schedules and tickets. As said, the Thalys tickets come with a discount when bought in advance. Those tickets are, however, only valid for a specific train. If you miss that train, the tickets are worthless.