Answer: You must use your imagination, but here's some help:
Step-by-step explanation:
Most of the people aboard the Titanic were very wealthy, therefore make your character (yourself) be on the Titanic for a business trip; meeting with a wealthy trader or just make yourself a rich tourist going on vacation. Add anyone you could be traveling with; maybe a sibling or a loved one. Describe the cabin and accommodations as luxurious and fancy, use specific details such as; "the walls were lined with gold, the seats covered in leather", etc. Write how you feel about the journey; maybe you're excited for the journey, maybe you're anxious or sea-sick, it's all up to your imagination.
Here's a template you can get inspired from:
"It's a beautiful day and me and my wife Cheri are so excited for our adventure aboard this fantastic cruise! If it weren't for the business meeting I have in New York, I probably would've completely blown this trip off! So glad that I didn't! Cheri decided to tag along on my business trip because she loves traveling, especially by sea. Me on the other hand, I get a little nauseous so let's hope I don't get sick...
-(XX:XX) The time is XX:XX and we've just set sail! They are offering lunch now and wow is it amazing! Not only was our cabin splendid, lined with gold and leather details, but so was the restaurant! The utensils were gold and the wine glasses made from pure crystal! The exquisitely dressed waiter brought us our dish served on a silver platter- a delicious red lobster! Freshly cooked!"
You get the gist, use your imagination and continue the story!