It can seem a bit overwhelming when you first start with screeps. A new tool has been developed by the team to simplify coding for new players.
Atom.io – Text Editor
The first thing you are going to want to do is to download Atom. After the program has installed go to File -> Settings -> Install and search for “screeps”
An Overview of the Screeps IDE
First thing you will want to do is link to your screeps account. Type in your user email and password and it will save an authentication token for future logins.
You can choose what code to use or create a project to code locally. In light blue you can see what code is currently deployed to the official server and the simulator.