Help!!

so just this week i have found out instead of sitting AQA biology gcse i am sitting edexcel igcse biology (long story don’t ask🙃) i am self studying and could really use some help.

I have been going off of the AQA specification this entire time and i don’t really know what the differences are between gcse and igcse. I would really appreciate any support or help as to what i should be doing differently in this lead up. My first exam is the 10th. Thank you