Call them and ask, or open up the chat at the bottom of the booking page and asking them to locate it (did you get an email about the hold?)

Test takes about 30 minutes (3 weeks ago for me, upon returning from Colombia). You will use a different testing area, as you are not coming from South America, but it should be about the same. Obv the quicker you get to the testing center, the quicker it will be for you