Need advice on how to prepare for British Physics Olympiad as a Year 13 student.

Hi all,
I'm new here, but was wondering if anyone who has sat the BPhO Round 1 paper has any advice in regards to preparation? For context, I study both Physics and Maths, but I am struggling with some of the content that we go through during training sessions (There is a training session on zoom which I was signed up to by my college, but some content is not on the A-Level spec hence I cannot solve these problems unless I learn the content from scratch). Does anyone have any relevant resources I can use for preparation? The paper will be sat mid-Nov and I am feeling massively underprepared, thank you :smile: