Error when I want to create bindings with Scons

Hello,
I'm following this documentation : https://docs.godotengine.org/en/stable/tutorials/scripting/gdnative/gdnative_cpp_example.html .
I'm trying to do the section "Compiling the plugin".
When I try to do :
`scons platform=windows`
I have an error :
```
scons: Reading SConscript files ...

scons: *** Path for option target_path does not exist: demo/bin/
File "C:\Users\lucas\Desktop\C++ projects\gdnative_cpp_example\SConstruct", line 26, in
```

## What I've done so far

I ran these command lines :
`mkdir gdnative_cpp_example`
`cd gdnative_cpp_example`
`git init`
`git submodule add -b 3.x https://github.com/godotengine/godot-cpp`
`cd godot-cpp`
`git submodule update --init`

Then I did :
```
cd godot-cpp
scons platform= generate_bindings=yes
```
I then created a demo folder where there is a godot project.
After that I created a folder src which contains gdexample.h, gdexample.cpp, gdlibrary.cpp.
I downloaded the Sconstruct given in the documentation.
My gdnative_cpp_example so far :
```
gdnative_cpp_example
| .git
| demo
| .import
| default_env.tres
| icon
| icon.png.import
| main.tscn
| project.godot
| godot.cpp
| .github
| __pycache__
....
| src
| gdexample.h
| gdexample.cpp
| gdlibrary.cpp
| gitmodules
| SConstruct
```
godot-cpp now includes godot-headers as a nested submodule so for me it's normal if I don't have a godot-headers.
Then I tried to do :
`scons platform=windows`
But here is my error :
```
scons: Reading SConscript files ...

scons: *** Path for option target_path does not exist: demo/bin/
File "C:\Users\lucas\Desktop\C++ projects\gdnative_cpp_example\SConstruct", line 26, in
```
Do you know what's wrong ?
Thank you.