What should a novice Bitrix developer study?

Question

PHP

Purpose: to learn how to make full-fledged sites on Bitrix. Competently and quickly customize components, solve complex problems related to improving the functionality of the site on Bitrix.
What can I do:

• Site administration on Bitrix (as a content manager)
  
• Creation of infoblocks, sections, elements...
  
• HTML (Good), CSS (+LESS, Good), twitter bootstrap, JS (+jQuery So so), PHP (Bad)
  
• I roughly understand what the system for arranging site files on Bitrix is. I almost understand what templates and components are. I can look at the code of the components, but 70% do not understand =)
  
• The demo is already downloaded, ready for experiments!
  

What should I read, what should I study? Interested in specific resources and specific goals.
Let's say there are 20 days to upgrade bitrix skills. What would you suggest?
Thank you!

Answer 1

Throw out Bitrix and sit exclusively here for at least 5 hours for 19 days. On the 20th day, return to the Toaster with a new question, where in the text of your question there will be something like

... PHP (Already better). What do you recommend to read?

.
You will be answered with links like this one . On XYZ day, download Bitrix again, return to the Toaster and ask questions specifically to Bitrix.

Answer 2

be sure to pull up php
be sure to read all the docks here https://dev.1c-bitrix.ru/api_help/

Answer 3

After the actions described by Denis and Maxim, I advise you to post the Bitrix Academy . You can watch course videos for free.