I have 889 in my sciences at GCSEs and am studying chemistry and physics at alevel. I am very chatty and easy to get along with and will be more then happy to help you with any problem you have no matter how silly or easy you think it might be we have all been there. I would use our first lesson to get to know you and the kind of things you are struggling with in the topics you choose and then go from there. In regard to what format I would use is really down to you different peoples minds work in different ways so weither that be a power point videos or demonstrations would all be specific to your learning. For example I personally learn best through videos I love watching revision videos on YouTube as I become easily distracted by my phone and so by being on my phone and revising it solves the problem! I also think that doing practice questions from previous exam papers is a great way for anyone to revise as it genuinely is the same questions on repeat. But I understand everyone learns differently I could never revise out of a text book but for other people it’s there go to method. Which ever way suits you best is how I would be willing to help you to achieve your goals and become more confident in your self and the subject.