code-d works best when folders are opened.
For a simple project open a normal folder using the Open Folder... button.
It's possible to add multiple folders to the workspace in VSCode using File -> Add Folder to Workspace....
Click File -> Open Folder... or Ctrl-Shift-P -> Open Folder... to open an empty folder as workspace for your project.
It is also possible to have projects with very few files and no dependencies whatsoever. For this you can also open a workspace as described above to have full feature access (such as build tasks and dependencies) but for quickly editing singular D files it is also possible to simply open them in VSCode. However auto completion is limited to only the standard library in this case, so it's not a good idea to work like this for bigger projects.
code-d contains project templates to quick-start the creation of projects.
Open an empty folder with the desired name for the project.
Continue by opening the command palette (F1 or Ctrl-Shift-P) and run code-d: Create new project. Follow the wizard to create the project.
You can now start coding away. To make this hello world project actually work, insert the following code:
import std.stdio;
void main()
{
writeln("Hello World");
}The example projects create a DUB project for you. (Noticable with the dub.json or dub.sdl file which is present at root level)
This means you have access to the whole D package registry and can use DUB as build tool too.
See DUB homepage for more information.
Next you might want to check out the chapter Building to see how you can now run your application.
However if you don't want to use DUB for building and dependencies, check out how to configure non-DUB projects
You might also want to explore the Editor Features code-d has to offer.