As I said, desires are literally just what she does and when she does it. If you go into the game and open the Cheat Tools mod window, you'll notice there are a bunch of sliders that move up and down, technically left and right but you know what I meant, over time. These determine the timing of her actions. Whatever is highest at any given time will happen the next time she is free of her previous action.
The traits really don't do a whole lot besides moving the desires closer to or further from being the one that is in most need of being dealt with, whichever is at the fullest on the list on the Cheat Tools window is the one in most need. Only some of them even have an effect other than adding points to desires based on the tables in the wiki I linked, such as loyalty with the ability to lower the chance of lesbian NPC interaction.
As far as what else there is to do, not a whole lot. Build, have sex with girls, create girls to have around the islands and have sex with, and collect materials is basically it.
I have another link for you that explains things a bit better.
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