a level politics please help

hey guys i really need need help i do edexcel a level politics. my teacher out of 3 has left school and for usa politics we're left with basically someone who is not a teacher. she was also teaching us the political ideologies and another teacher is now doing that with us but...they're a history teacher... so i'm basically left with one actual politics teacher. so far i have no idea what i am doing now. i don't understand the us topics supreme court and civil rights, democracy and participation and i will probably not understand a word of comparative approaches when i get to them. i also have no idea about liberalism and so far we're learning socialism which i feel so underconfident in. i am starting to lose interest in the subject now, i did the worst in it in my mocks too and i feel so upset because i really want to get good grades and achieve my potential.

please please can someone recommend me sites to learn these topics at because i already pay fees for school i don't want to spend more money on a tutor so i want to find good websites that can help teach me the topics in the course