Update guide

Author: karnkaul

guide/src/initialization/instance.md

@@ -6,7 +6,7 @@ Instead of linking to Vulkan (via the SDK) at build-time, we will load Vulkan at
 1. In `app.cpp` this line is added to the global scope: `VULKAN_HPP_DEFAULT_DISPATCH_LOADER_DYNAMIC_STORAGE`
 1. Before and during initialization `VULKAN_HPP_DEFAULT_DISPATCHER.init()` is called
 
-The first thing to do in Vulkan is to create a `vk::Instance`, which will enable enumeration of physical devices (GPUs) and creation of a logical device.
+The first thing to do in Vulkan is to create an [Instance](https://registry.khronos.org/vulkan/specs/latest/man/html/VkInstance.html), which will enable enumeration of physical devices (GPUs) and creation of a logical device.
 
 Since we require Vulkan 1.3, store that in a constant to be easily referenced:
 
@@ -54,9 +54,13 @@ Create a `vk::InstanceCreateInfo` object and fill it up:
 		extensions);
 ```
 
-Add a `vk::UniqueInstance` member, create it, and initialize the dispatcher against it:
+Add a `vk::UniqueInstance` member _after_ `m_window`: this must be destroyed before terminating GLFW. Create it, and initialize the dispatcher against it:
 
 ```cpp
+	glfw::Window m_window{};
+	vk::UniqueInstance m_instance{};
+
+  // ...
 	m_instance = vk::createInstanceUnique(instance_ci);
 	VULKAN_HPP_DEFAULT_DISPATCHER.init(*m_instance);
 ```

guide/src/initialization/surface.md

@@ -1,6 +1,6 @@
 # Vulkan Surface
 
-Being platform agnostic, Vulkan interfaces with the WSI via the [`VK_KHR_surface` extension](https://registry.khronos.org/vulkan/specs/latest/man/html/VK_KHR_surface.html).
+Being platform agnostic, Vulkan interfaces with the WSI via the [`VK_KHR_surface` extension](https://registry.khronos.org/vulkan/specs/latest/man/html/VK_KHR_surface.html). A [Surface](https://registry.khronos.org/vulkan/specs/latest/man/html/VkSurfaceKHR.html) enables displaying images on the window through the presentation engine.
 
 Add another helper function in `window.hpp/cpp`:
 
@@ -17,7 +17,7 @@ auto glfw::create_surface(GLFWwindow* window, vk::Instance const instance)
 }
 ```
 
-Add corrseponding members to `App` and create the surface:
+Add a `vk::UniqueSurfaceKHR` member to `App` after `m_instance`, and create the surface:
 
 ```cpp
 void App::create_surface() {