The proxy vote space/square/box is located above the FOR, AGAINST, and the ABSTAIN boxes.
See Step 1 : "Appoint a proxy to vote on your behalf".
In there you will find that you can nominated either the Chairman of the meeting or Whoever else you elect to vote on your behalf. Most importantly, you can select in which way you want your vote to count and "YOUR PROXY" is obliged to vote along your instructions. Unless of course you are intending to attend the meeting and vote yourself.
Me personally I wouldn't select the Chairman of the meeting to represent me at that meeting as he would be the last person on Earth that I would allow to vote on my behalf. (Even though he would still be requested/required by law to vote your shares in the way you have selected.)
I simply wouldn't give him that simple pleasure of representing me. But that's me....
