People here seem to think that each person gets multiple votes, but that is not true. It would not be fair. You get one vote, and it says so on the voting page that only one vote is allowed per person no matter how many projects you are on.
You are misunderstanding what it says. The election is using Approval Voting (see the Wikipedia article), which means you can vote for as many of the candidates as possible. When it says you can only vote once, it means you can load the voting page and click submit once, you can select multiple candidates while on that page, though.
Have you actually tried clicking the "Vote" link (you can cancel and vote later if you haven't made up your mind yet)?