What do I revise for!?

I was given my practice exam time table for year 9 last week and I have them in two weeks time. I am someone who really struggles to get themselves to revise to begin with and especially to keep focus when actually revising, however I did actually sit down to revise today and just thought...

"I have absolutely NO IDEA what to revise."

All it says on my exam timetable is that I have a 'Core science higher paper 1' and that gives me no clues as to what to revise for. Enzymes? Covalent bonds? Speed of light? I don't know!

Please help me if you know what i should revise for on these papers (AQA) or sights that would tell me! thanks