Download the official app.
Give yourself 2 weeks.
Practice them over and over and over and over!
Test yourself everyday day!
A test is like 10-5mins so you can easily squeeze in 8 practice tests a day or even more if you're dedicated. Can do this on the bus, on the toilet, chilling.
The theory is more 85% memory/common sense and 15% knowing the slight difference between the answers.
That's it. Practice the questions and test until you getting over 90% consistently.
That's what I did and passed first time. easy. GOOD LUCK