docs: add exercises page

docs/pages/2_features/main.md

@@ -44,9 +44,8 @@ dive into the documentation of each class and function.
 ## What we don't have and where are we going
 
 The engine is still in its early stages of development, and thus we're missing
-a lot of features. For example, we don't have physics yet, and the editor tools
-are very barebones - you can't even load a scene from a file yet. There's no
-scripting language, thus you will have to write all your game logic in C++.
+a lot of features. For example, we don't have rigid body physics yet, and the editor tools are very bare bones.
+There's no scripting language, thus you will have to write all your game logic in C++.
 
 Making a game with the engine is still very painful. Our goal is to make
 **CUBOS.** usable for game jams by people who are not on the team. This means a

docs/pages/4_exercises/main.md

@@ -0,0 +1,60 @@
+# Exercises {#exercises}
+
+This page contains challenges designed to help you start working with **CUBOS**.
+We recommend that you start by reading the @ref getting-started "getting started" and @ref features "features" guides.
+
+## Creating a new engine sample
+
+Before moving on to the actual exercises, lets start by creating your own empty sample, which will be expanded upon the next steps.
+
+Start by creating a new folder in the `engine/samples` directory, i.e., `engine/samples/my-own-sample`.
+Make sure to add a `main.cpp` to that folder, with the following base code:
+
+```cpp
+#include <cubos/engine/prelude.hpp>
+
+using namespace cubos::engine;
+
+int main()
+{
+      Cubos cubos{};
+      cubos.run();
+}
+```
+
+The final step is to add your new sample to the CMake configuration, at `engine/samples/CMakeLists.txt`.
+Open that file, and add a new line of the form `make_sample(DIR "my-own-sample" ASSETS)`.
+
+If you now reconfigure CMake, you should be able to launch the target `engine-sample.my-own-sample`.
+Don't worry if nothing shows up yet - in **CUBOS** you only get what you ask for, and in the code above we didn't do anything except run an empty application.
+
+## Showing a cube
+
+Try making your sample open a window and show a simple voxel cube! To do this, you will need to:
+1. Add the @ref renderer-plugin "Renderer plugin".
+2. Create a @ref cubos::engine::VoxelPalette "VoxelPalette".
+3. Create a @ref cubos::engine::VoxelGrid "VoxelGrid".
+4. Create a @ref cubos::engine::PointLight "PointLight".
+5. Create a @ref cubos::engine::Camera "Camera" and add it to @ref cubos::engine::ActiveCameras "ActiveCameras".
+
+You can take inspiration from the @ref examples-engine-hello-cubos "Hello CUBOS" @ref examples-engine-renderer "Renderer" samples. 
+
+## Replace the cube by an actual voxel model
+
+Of course we don't expect developers to generate their voxel models through code!
+Change your sample to show an actual voxel model, created and stored in a `.qb` file.
+You can create one using [MagicaVoxel](https://ephtracy.github.io/), or simply download an existing model from the internet.
+
+**CUBOS** doesn't handle `.qb` files directly: it only supports `.grd`'s and `.pal`'s, our own formats for voxel grids and palettes.
+You can use **QUADRADOS** to convert a `.qb` to a `.grd` and `.pal`. Check out its @ref features-quadrados "feature guide" for more information.
+
+Take a look at the @ref examples-engine-voxels "Voxels" sample to figure out how you can load those files into the actual sample.
+
+## Move the voxel model on input
+
+Make the model you added previously move when some buttons are pressed. You will need to:
+1. Add the @ref input-plugin "Input plugin".
+2. Create an input bindings asset.
+3. Add a system which uses the @ref cubos::engine::Input "Input" resource to move the model.
+
+Check out the @ref examples-engine-input "Input" sample for inspiration.

docs/pages/main.md

@@ -25,6 +25,9 @@ quick overview, this is the place to go. You can also take a look at the
 In the @ref examples "examples page" you can find examples on how to use
 specific parts of the engine.
 
+Consider taking a look at the @ref exercises "exercises page" if you want some
+challenges to help you understand how to work with **CUBOS**.
+
 If you're looking to contribute to the project, make sure you read the 
 @ref contribution "contribution guidelines", which introduces you to the
 project's conventions and code style.