There are not many 'simplified' resources on offer. The best ones are Routledge - AS Philosophy. On their website you can find topic by topic revision content - as well as key ideas, critical analyses which are directly linked to the AS Philosophy specification. There are some youtube videos which are helpful in digesting the idea. Stanford Philosophy websites were helpful, well I had to ask many questions to my teacher though.
You can find useful books at the end of each topic in the AQA AS Philosophy book as well.
Hey, have you tried writing the definitions of the terminology and analogies - for example in Reason and Experience, define conceptual schemas + describe Leibniz's marble analogy (innate ideas)
Go over them, make sure you understand each definition and attempt as many past paper/practice questions to prepare your answers