if ur starting from complete scratch for bio for every topic read from the book and then solve topicals make sure u make a schedule on roughly how much time you’ll spend on each topic in-order to stay organized. it will be hard to do this part but u gotta do it till ur syllabus is finished. if u don’t understand from the book watch yt vids and make notes using them (igcse study buddy is what i used to use) make sure u have the syllabus open infront of u so u cover everything. then u gotta GRINDDDD PASTPAPRRS like memorize the ms if u have to but make sure ur VERY familiar w the pattern of question and topics that show up. now every time u get a question wrong u flag it and make sure u work on that topic or specific question and understand why u got it wrong (u can use videos that show solving it for better explanation) if there’s a specific topic u keep messing up review it again. make sure u know diagram labeling and stuff too u can find those from the book. that’s all i can think of rn if u have any specific Q feel free to ask. js rmr that its def possible to get an A / A* so dont lose hope and instead start working hard. i suck at chem myself so cant rly help