Help with multiple colors and duplicate stitching

I have knitted a bit before and can do most of the basic stuff, but I’ve found a pattern that is more complicated than what I’ve done before, and I need some help.

This is what I want to knit:, and I am a little uncertain about how to do the dark blue and white stitches.

I know there are a few methods for knitting multiple colors, but I don’t know which one would be best to use. And what exactly is duplicate stitching?

Duplicate stitching is when you sew on the other colors when you’re finished with the knitting. If you Google it, you’ll find several sites that tell you how.

Check out intarsia as well, it is probably what you would use for the dark blue areas. The Tardis wouldn’t have the door on all four sides would it, so it seems like you would only make that complicated side once?

Nope, the Tardis looks like that on all four sides. I will check out the video for intarsia, then, and look for a site with instructions for duplicate stitching. Thanks to both of you for your help.