committing requested changes in stages.

Author: gpx1000

antora/modules/ROOT/nav.adoc

@@ -52,4 +52,13 @@
 * xref:15_GLTF_KTX2_Migration.adoc[Migrating to Modern Asset Formats: glTF and KTX2]
 * xref:16_Multiple_Objects.adoc[Rendering Multiple Objects]
 * xref:17_Multithreading.adoc[Multithreading]
+* xref:Building_a_Simple_Engine/introduction.adoc[Building a Simple Engine]
+** xref:Building_a_Simple_Engine/Engine_Architecture/01_introduction.adoc[Engine Architecture]
+** xref:Building_a_Simple_Engine/Camera_Transformations/01_introduction.adoc[Camera Transformations]
+** xref:Building_a_Simple_Engine/Lighting_Materials/01_introduction.adoc[Lighting & Materials]
+** xref:Building_a_Simple_Engine/GUI/01_introduction.adoc[GUI]
+** xref:Building_a_Simple_Engine/Loading_Models/01_introduction.adoc[Loading Models]
+** xref:Building_a_Simple_Engine/Subsystems/01_introduction.adoc[Subsystems]
+** xref:Building_a_Simple_Engine/Tooling/01_introduction.adoc[Tooling]
+** xref:Building_a_Simple_Engine/Mobile_Development/01_introduction.adoc[Mobile Development]
 * xref:90_FAQ.adoc[FAQ]