Civilization 6 how to put land units on sailboats

At the beginning of the game, your land units can't enter any water bags. When you gain navigation skills, the builder can enter the coastal water unit. With astronomical navigation, businessmen can get on board. After shipbuilding, all units can board the ship. When a unit is allowed to board a ship, it is necessary to move the unit to a coastal cell, and then click the action option on the ship. After clicking on board, the unit must enter the waters.