Add docs for additional install methods (#1059)

doc/installation_manual.md

@@ -0,0 +1,35 @@
+@page installation_manual Manual
+@tableofcontents
+
+## Building from Source (Official)
+
+Clone and build the project using CMake:
+
+```bash
+git clone https://github.com/ArthurSonzogni/FTXUI.git
+cd FTXUI
+cmake -S . -B build -DFTXUI_ENABLE_INSTALL=ON -D
+cmake --build build -j
+sudo cmake --install build
+```
+
+Once installed you can use it in your CMake projects by adding the following to your `CMakeLists.txt`:
+
+```cmake
+find_package(ftxui REQUIRED)
+add_executable(main main.cpp)
+target_link_libraries(main
+  PRIVATE ftxui::screen
+  PRIVATE ftxui::dom
+  PRIVATE ftxui::component
+)
+```
+
+
+<div class="section_buttons">
+
+| Previous          |
+|:------------------|
+| [Getting Started](getting-started.html) |
+
+</div>