Hi, I think the best thing you can do is make sure you do your homework of the the practice materials that they send you and maybe do a lil extra research on the mechanical comprehension side of things if you are not one of those that are mechanically minded.
I've been through the whole process with EMT and I think if you can be patient (as hr companies can be a little slack) but just persevere and if your head is screwed on you'll be fine!
All the best anyways!