Welcome to A-level Computer Science. There are two papers which contribute to your result, worth 40% each, and a project-based "Non-Examined Assessment" (NEA) which provides the remaining 20%. In very broad terms, Paper 1 is programming-focused and Paper 2 covers the rest of the theory component.
The subject content for Paper 1 and Paper 2, at both AS and A-level, is covered here.
The "Craig n Dave" YouTube channel provides in-depth videos covering all of the A-level Computer Science specification, including advice on the project (the Non-Examined Assessment, or NEA). Click the logo on the left to see the videos in specification order.
The Personal Learning Checklist (PLC) for AQA A-level Computer Science contains a list of everything you need to know and understand, with space for you to assess your level of understanding. Click the doc on the left to download a PLC.
Textbooks are provided using Classoos. You can access Classoos via the web, and there is also an Apple/Android app that you can download so you can access it on your phone or tablet without WiFi. Click the logo on the left.
The A-level Computer Science Wikibook isn't as detailed as the main text book, but is a good resource for revision (click the logo on the left).
Terminology is vital for A-level Computer Science. Quizlet can be helpful for learning important words, but don't rely on it too much as having a good understanding is crucial, so you need to work beyond Quizlet's level as well.
A-level Computer Science builds on your programming skills from GCSE. Learn to program in C# with this free tutorial.