As mentioned, get the DVD or an app that runs you through the test. Study-up using the questions, there is also still a physical book you can buy, I think even supermarkets have it on their book aisle, or WH Smith.
In one sense it IS easy, but I would disagree with kraftie -- you DO need to study the manual. This is the British theory test and the computer generates random questions from possible hundreds. You do need to make sure you learn what all the road signs mean, what the different shapes of the signs mean, what road markings mean (long broken white lines or short broken white line, etc.)
And you have to memorize stopping distances, and which colour lights different emergency vehicles use. All of these questions may come up randomly during your actual test. It's randomly generated and you have to learn everything even though only a portion may come up in the questions.
Also, there are websites and apps that test you for the hazard perception test. This is also part of the theory test. They will run footage on the screen, taken from the point of view of you, the driver, driving along a road. Various hazards will come up, such as a car pulling out of a side road, a cyclist on a narrow road, a woman with a baby buggy about to cross at a crossing.
You have to click the mouse as soon as you spot the potential hazard. A hazard is considered to be anything that happens that may be anticipated to cause you to either brake your vehicle or have to alter your course.
It's tricky in the test though, because if you just keep clicking in appropriately, you lose points in that clip even if one of them was a correct hazard.
Get a hazard test app and a theory app and just swot up and practice as much as possible. The good thing is the theory test is multiple choice and even if you forgot the actual answer, it's easy to pick it out among clearly unsuitable choices.