When creating a new project, what should I do first?

I have this doubt, and I would like to be very organized at the time I start my new serious project.

So, once I create the project and editor opens for the first time, what’s next?
Should I edit the editor appearance? Or the project settings? like the physics, input, rendering options, etc

Maybe firstly should I do my game icon and splash images?

And at the time of working in the actual game, should I start building the menus and the UI or should I start directly with the player functionality?

In your opinion, what’s the best way to start working into the game? Or what’s your workline?

I would like to know what you think; my objective is to get a solid and nice base to start building on top my game.

Make a working prototype before worrying about an icon and splash image

Start with any kind of version control like git or perforce.