The STEP II papers share the same syllabus as STEP I, but the questions are harder. We therefore recommend that you should prepare by working through the first 18 Foundation modules before tackling these. From January onwards, we suggest you work on the remaining weekly Foundation modules as they are released alongside the STEP II modules.
Each of these STEP II modules consists of a selection of STEP II questions, together with hints and solutions. The modules also contain "topic notes" which consists of useful formulae you should be aware of, together with some general hints and advice.
These modules can be tackled in whichever order you like, but we would suggest that you do the "STEP II Calculus" module first, followed by the "STEP II Curve Sketching" module.
There is more information about the different module types here.