How do I get out of La guardia airport to take the shuttle to the port of Manhattan?

Sorry my language skills are not that good however I think you're asking about transportation from the La Guardia Airport to Manhattan cruise terminal in which case there are transfer buses and plenty of taxis ber and grab ground transportation vehicles available

Sorry

If you are dealing with an agency, find out. Otherwise simply take a taxi. (There will certainly be some when you leave the airport)