URGENT!

Can someone pls enlighten on on how this works-

When u finish ur 5th semester of Basic Sciences, how long do u normally take to sit for ur USMLE STEP 1? Can you take the exam as soon as u r done with the 5th semester if u are ready for it?
Once you have taken the exam, how long is it b4 u can actually start ur clinical rotations? In essence, how long do the results take and from then on, how long would it take for MUA to arrange ur placements at teaching hospitals?

Also, being Canadian, after I'm done with my 5th semester, would i have to come back to Canada to take the USMLE's or can I stay on the island and take them?

Any help would be much appreciated.

Thanx