Hello !
There is a free complete course by Victor Mallet.
It is about how to create a basic FPS :
https://openclassrooms.com/courses/creez-votre-propre-fps-en-webgl
It is in french but with a translator, you may understand :
https://translate.google.com/translate?hl=en&sl=fr&tl=en&u=https%3A%2F%2Fopenclassrooms.com%2Fcourses%2Fcreez-votre-propre-fps-en-webgl