You can take one bathroom break of up to 5 minutes during the exam. If you require a comfort break you should:
1) Request a chat with your invigilator by clicking the speech bubble at the top of your screen.
2) Once the invigilator has opened up the chatbox, you should tell them that you are leaving your desk to use the bathroom. You do not need to wait for their response before leaving your desk.
3) Once you've returned use the chat function again to let the invigilator know you have returned. They may wish to verify your ID once you return.
The exam is not paused during a comfort break and the exam timer will continue to run.