Here’s the Main Deck before I start…

First thing in going to do is to remove the Bollard guides that come up from the Bulkheads.

Here’s a good Article about how to do it at Modelers Central…

One thing you have to do with deck planks to simulate the caulking that’s in between each plank using like a number 6 b pencil and what you do is you get a few and then you scribe a bunch of them at once. I’d say maybe you like 5 80 mm long planks and just put them on a clip and just use a pencil across them all. I made the mistake of doing it one at a time and it’s better to get a bunch at once.