When you first start to learn to code, you will likely be introduced to many things you don’t understand.
This often leaves people (myself included) feeling like they are not learning anything, or there is too much to learn.
Its often a process that takes a while before results start to appear.
Many learning platforms will try not to give you too much information at once.
But they do use environments similar to what you will be using when making your own projects.
I don’t want to confuse you or lead you down any rabbit holes, so this is just the basics:
When writing code, you write it in a file, that file is read by the browser as instructions for displaying content.
The ‘Preview’ is what your code looks like when the browser reads your code.
The console may display errors and other information when writing code.
When you are introduced to something new, try using a search engine to find out more about it.
There are many sites out there with tag, attribute, selector, etc lists that will give you the definition of these things.
freeCodeCamp uses a project based learning method,
this mean you will be introduced to things using projects in small steps, then you will go on to complete a project all by yourself.
(those are where you will learn the most)
Its likely many of your early questions will be answered by going through the first few projects.
If you still have questions or are confused about something, you can search for resources online and ask the community about it, when asking a question its often helpful to include as much relevant information as you can, such as links and images ( as you have done 
).
There is also a ‘general’ subforum where you can ask any question 
