Hi, I did the GCSE last year, I'm not too sure on the rest. But in typically every case for GCSE, they will give you the choice to either do your own pseudocode, or a flowchart.
The general shapes you want, oval = start/end
Parallelogram = Input/Output
Wide Diamond = if case, or a decision of any kind
Rectangle = a Process
For doing if cases or any sorts of decisions, you wanna be doing arrows consistently, showing every possible stage
Make sure you're communicating the process clearly.