how do i get 5 As at higher

First- change your mindset. If you don't change it, then it is most likely that your academic success will only fall, not grow.
Don't be too upset with the prelim results - the reason why schools make you do them is to a) let you have a feel of how higher exams are like b) let you realise where are your weak points and your strong points, in terms of time, knowledge etc. c) so that students start to feel the pressure- that they need to start putting in the effort and prepare for the final exams before its too late (by the way, I am not implying that this is the case for you, but this is reality.)
Motivation wise- do you have a goal in mind yet? Like what course/subject you want to do in university, or what you university you want to strive for? Take some time and figure things out, and once things are clear and you know the what you need to do to get there, then there is a reason for you to strive high and you will be motivated to work hard.
The best revision is to do past papers- when you don't understand them, go ask your teacher for help. You won't learn if you don't ask questions. If they aren't available, then go search online, on YouTube. You will understand how the exam board (SQA) asks questions and what comes up most often. Also, fully understand the course specification- that is the bible for examiners when they are creating questions.
You can do this!! 💪

i do have a career in mind, i want to go into dentistry in dundee uni which asks for 4As and 1D for highers but i want to get all As to make sure i can secure a spot. am just worried that it’s not going to be possible for me to achieve all As by the times that exams are here.