Page templates for beginners

Hi there
i have been trying to figure out if this is the right option for me.
I have minimal capital so I am a beginner that is learning as I go. My website overall will be busy and definitely require more than what i am capable and therefore for the basics, I am looking at adding a membership / Subscription monthly. Additionally I need to have a calendar for events and workshops that people will need to be able to register and pay for events and classes.

My questions
1 - How to create or modify template pages?
2 - Why does my header and footer not carry through the other pages
3 - Is there a way to allow paid members discounts to the various events?
I am a beginner that learns quick.