Actualiser README.md

Signed-off-by: Alexandre_1a <alexandre_1a@noreply.localhost>

README.md

@@ -1,3 +1,24 @@
 # 3DS
 
-A small repo, to test some 3DS homebrews
+A small repo, to test some 3DS homebrews  
+
+## Running
+You need a modded 3DS with Luma3DS and the Homebrew launcher installed.
+
+### Building from source
+To build this project, you can :
+- Use the `makefile` provided, with the default devKitPro packages
+- Use the `flake.nix` for nix-based setups.
+
+#### Using make
+Just clone the repo, and run `make`
+
+#### Using flakes
+Same as the makefile method, but you can use the devshell with `direnv` or `nix develop`.  
+You can also use `nix build`.
+
+## Architecture 
+This project uses the same architecture as my Vulkan engine, allowing for a more modular approach, and reusable compoments.  
+This project also uses a "single header" architecture, popularized by STB.  
+This means that all game code is contained in a header, with guards.  
+To use the implementation, you need to use a `#define ENGINE_IMPL` for example.