Firstly, don't worry if this is your first week or two having ever studied Computer Science - it's fairly normal for most people starting A-Level to be in exactly the same position. Realistically you're not going to be expected to have learned much more than a few basics in the space of a few weeks.
The first hurdle to get over is to make sure you're happy and comfortable with the syntax of a programming language and able to use the tools to make something which works at a basic level (e.g. "hello world", counting numbers, writing out a shape of a triangle to the screen, etc.)
The most important skills in computer science are all about analysis, problem solving and computational thinking. These aren't skills which can be learned by watching videos or reading books - the only way is to physically sit down and just practice at them by analysing and solving problems with the programming language.
One part about it is being able to look at a big, complex problem, being able to understand what the problem means, identifying important bits of information, and breaking the problem down it down into many smaller, simpler, managable pieces until you're not just solving a single big problem, but you're solving lots of nice small, easy problems instead -- then the "big" problem is really just about fitting smaller pieces together.
For example, a problem such as:
"Ask the user to enter a number, if the number they've entered is even, print it to the screen, otherwise ask them again".
- There's 3 different problems there already which can each be solved on their own with different code/instructions:
1.
Ask the user to enter a number
2.
If the number they've entered is even, print it to the screen
3.
otherwise [... it's not even...] ask them again
Don't solve a single problem when you can solve 3 small ones and put those 3 together when you're done.
Computational thinking is learning how to "think" like a computer - The 3 basic capabilities of a computer are about
1.
Running instructions in sequence
2.
Logic-based decision making (selection)
3.
Repetition of instructions.
The skill is all about being able to express a solution to a problem step-by-step in those terms - i.e. being able to break the solution down into small enough steps so that you can describe each strep using an instruction in a programming language.
Start out with some simple programming problems to begin with. To coin an analogy, nobody learns to climb by starting at foot of Mt. Everest, instead they start with something managable.
Hopefully the kinds of assignments you're getting from your course will gradually increase in complexity, so if you've got a bunch of assignments which you're finding too difficult then go back to some earlier ones and practice with those. Any programming or Computer Science textbooks should also have some problems to try. Keep trying until it just "clicks" -- also take the time to explore and try different things with the programming language just to get a feel for what works and what doesn't. Curiousity is a virtue!
At first you'll get a lot of syntax errors which prevent your program from running - realistically these will take a lot of your time in the first few weeks/months until you get comfortable with the language. If you ever run into any problems, then chances are it'll be a problem somebody else has encountered and solved before. Make use of Google to look for the ways other people have solved the same problem. Something like a syntax error is usually easy to search online because you often have some kind of error code, and maybe some text that you can just paste into Google or even
https://www.stackoverflow.com to find other similar questions/answers. Google and StackOverflow should be your two most important websites - many of the best programmers in the world are found on StackOverflow answering all kinds of questions, and you'll often find some really great information there.