building a D app with multiple source files

[nikki via Digitalmars-d-learn]

Hello, I am completely new to D and have been paying around with
the tutorials, some docs and little test programs.

Now I want to try and use https://github.com/elvisxzhou/artemisd
for little gamedev experiment but I am running into build issues.
That project doesn't have a Makefile in the repo, and I am on
linux so I need to build it on the terminal,

I've read about rdmd (and tried it without success) and found a
few 'general' usage Makefiles, can't get any to just work when I
type 'make all'.

in the repo I linked to (artemisd) there are dozens of source
files in various folders, and an example i have to compile at the
same time I think.

could someone show me how it's done ?