2 questions about the web development(React+Django)

i am trying to go into the web development path and trying to React+Django Combination to get started. But i am having some doubts related to this.

i. we can build a webpage both with Django and react. Then why are we categorized them as frontend and backend ? Though i know frontend means what user sees and backend means the logic behind the scene that helps the frontend to thrive. Can't we just use just one Django or React ?

ii. Suppose i followed a tutorial to build 2 projects using react and Django separately. Then we will deploy . What are next things to learn to make it happen?

i am asking long questions as am a noob here. Hoping for a detailed explanation.