So, i'm developing myself the website of my start up business. I'm done with HTML, CSS and PHP essentials. Now i dont have a clear vision where i should aim my focus on.

The website itself will have a pretty simple backend, since my product is video based - a 12 week video course. Not even close to the complexity of a app. Check out what i need to build:

1) A free/public area with static pages, like the home page, contact page, about us page etc.

2) A area for a 1 week free trial of the product, with the respective videos of the first week of the course

3) A payment page,where people of course will go to pay for acess to the whole video course.

4) A premium area where the members who paid for the course can log in anytime and have the whole video course available for them. The acess to this area needs to be for only 97 days (3 months and 7 days)

5) A second payment page, now for our subscription service that will be offered after the main course.

We'll offer periodic videos for a low fixed monthly price, in a different area of the web site + complete acess for the main video course already attended by the user for unlimited time, as long as the member pays the low monthly fee.

So i need to build this area where the periodic videos will be placed.

6) I need to build and know how to manage a data base with user log in information, etc

7) I need to build all this with a simple, clean, nice design

So... with those specific needs, what should i learn next to get them done?

Thanks in advance!