Problem trying to setup cocos2d-x-3.9

Hi forum. I have been having this problem with cocos2d-x-3.9 when trying to do the command python android-build.py -p 23 cpp-tests. It comes up with a strange error that looks like this.

“Android platform not specified, searching for a default one…
Can’t find right Android-platform for project : “C:\Users\nell\Downloads\C++_Game_Developing\cocos2d-x-3.9\tests\cpp-tests”. The Android-platform should be equal/larger than 10.
Build dynamic library for project [ C:\Users\nell\Downloads\C++_Game_Developing\cocos2d-x-3.9\tests\cpp-tests ] fails!”

Does anyone know how to resolve this issue. Thanks for reading

(By the way I am using ndk-r10c)

Hello @ThePixelCoder

Do you have Android 23 sdk in platform for Android SDK. !!

How do I find that out?
(First time developing for android on a PC)