Arriving by air: If you were booked through the cruise line, there will be people to meet your flight. They will have signs. They used to take your luggage directly from the airline for you but now they ask you to identify your luggage when it comes off the carousel and then they will take it to the ship. So you really don't have to handle it much. Keep your carryon luggage with you. You'll be loaded on a bus and taken to the port. If you booked air on your own you can buy an airport transfer separately from the cruise line. Otherwise, it's your responsibility to get to the port. However, if you come in a day or so early it's up to you to get to the port.
Arriving by car: Ports have parking structures just like airports where you can leave your car. Drive up to your dock and drop off your luggage with one of the porters. Then park your car. Keep your carryon luggage with you.
Checkin: Most cruise documents state checkin time. Keep in mind that the ship has just disembarked a load of people so they need some time in between to prepare the ship. They make turnarounds just like airlines. You'll go through security just like at an airport although here you are allowed more leeway with items in your carryon. They won't confiscate pocket knives or liquids. Then you'll go to a counter and present your documents. Depending on the line you'll also get a boarding number or just stand in line to board. We prefer the number system so you can sit down and wait until your number is called. On HAL Suite passengers get priority passes. Some other lines provide that too.
On Board: Some ships will have stewards escort you to your cabin, others you'll be on your own. That's why it helps to have seen the layout of the ship beforehand. You can find this in cruise brochures or on their websites. Throughout the day stewards will be delivering luggage but don't worry if it's not there before you sail. It does take time to distribute all the bags. If you've checked in early, you can usually go to the buffet for lunch. Walk around the ship and get your bearings.
Sailing: Shortly after the ship sails (or sometimes before) there will be a Life Boat Drill. Attendance is mandatory. On some ships you must take your life jackets and go to your life boat station. Information on where this is will be in your cabin and there will be people directing you there when the time comes. Take this seriously, it could mean your life. Many people joke about it, especially frequent cruisers but there are lots of people onboard who have never cruised so this is important for everyone. Don't give the crew grief over having to endure it, it's the law.
After all that is over you're ready for your enjoyable cruise!
As much as you hate it, this time will come.
Day before last day: There will be a presentation about what to expect. You will get your preliminary bill so you can reconcile it. You will also get luggage tags that are color coded. That evening you must put your luggage outside your cabin door before you go to bed. Keep your carryon. Your luggage is collected and will be transported to the dock the next morning.
Last day: You will be asked to vacate your cabin, usually by 9 am. This is so the room stewards can prepare the cabins for the next group. You can wait in any of the public areas. Suite passengers are given a special location or allowed to reamin in their cabin, and often can disembark whenever they choose after clearance. The ship has to clear immigration and customs. Any non-US residents will have to see an immigration officer at a designated spot on the ship. (If you're getting off in a foreign port US residents will also have to see immigration.) All passengers must have settled their shipboard accounts. They don't let anyone off until this is done. You'll hear announcements calling people names. This is because they didn't pay their bill or they need to go through immigration. Finally, after everything is cleared they will begin calling colors for the various groups. Only go when your group is called. You turn in the card as you leave the ship.
Off the ship: You will find your luggage. It will be in areas based on your color coded luggage tags. If you have cruise line transfers they will then take your luggage and you to the airport. Some ports have checkin for airlines right at the dock. There are plenty of porters around to help with luggage.
Flight Schedules: Now that you see what you have to go through, you can understand why, if you're booking your own flights, you don't want to book them before noon. Disembarkation usually starts around 9:30 or 10:00. The bigger the ship, the longer the process. Take that into account plus how far you are from the airport and getting through airport security before booking your return flight.
The End - but if you're like many, this will not be your last cruise.