UCAT Keyboard shortcuts can be used to navigate each subtest if you find it preferable. Nevertheless, with limited time in the exam, they can be essential and help save a bit of time.
The UCAT keyboard shortcuts can be used at any time depending on the current screen being viewed. However, they cannot be used to pick your answer, this can only be done with a mouse to select an option or in some cases drag and drop. I strongly recommend practising shortcuts when attempting questions on the UCAT platform. This might help with overall pace in each subtest.
You can explore all the above shortcuts in the tour tutorial provided on the official UCAT website, which illustrates all the functions used in the test including how to answer and review question. When using an online UCAT course, I highly recommend to practice and get into the habit of using them before test day. I don’t recommend learning all of them, pick a few that you think will help you out.